diff --git a/conformance-search/src/components/BoxComponent.tsx b/conformance-search/src/components/BoxComponent.tsx
index 5d4e3c35..f6891585 100644
--- a/conformance-search/src/components/BoxComponent.tsx
+++ b/conformance-search/src/components/BoxComponent.tsx
@@ -324,7 +324,7 @@ export default function BoxComponent({ box }: { box: SearchResultRefined<Box> })
                         </span>
                     </div>
                 </Drawer>
-                <Drawer title="Syntax">
+                <Drawer hidden={box.item.syntax === null} title="Syntax">
                     <SyntaxHighlighter
                         customStyle={{
                             fontSize: "0.75rem",
diff --git a/data/file_features/published/3gp/female_amr67DTX_hinted.json b/data/file_features/published/3gp/female_amr67DTX_hinted.json
index a9e7cc1a..034b0079 100644
--- a/data/file_features/published/3gp/female_amr67DTX_hinted.json
+++ b/data/file_features/published/3gp/female_amr67DTX_hinted.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track", "RTP hint tracks"],
+  "features": ["RTP hint tracks"],
   "notes": "",
   "license": "",
   "rel_filepath": "./female_amr67DTX_hinted.3gp",
diff --git a/data/file_features/published/3gp/female_amr67_hinted.json b/data/file_features/published/3gp/female_amr67_hinted.json
index 193b6718..298f7177 100644
--- a/data/file_features/published/3gp/female_amr67_hinted.json
+++ b/data/file_features/published/3gp/female_amr67_hinted.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track", "RTP hint tracks"],
+  "features": ["RTP hint tracks"],
   "notes": "",
   "license": "",
   "rel_filepath": "./female_amr67_hinted.3gp",
diff --git a/data/file_features/published/3gp/male_amr122.json b/data/file_features/published/3gp/male_amr122.json
index a22a359f..ff5b7cc6 100644
--- a/data/file_features/published/3gp/male_amr122.json
+++ b/data/file_features/published/3gp/male_amr122.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./male_amr122.3gp",
diff --git a/data/file_features/published/3gp/male_amr122DTX.json b/data/file_features/published/3gp/male_amr122DTX.json
index 107b395e..8ce63255 100644
--- a/data/file_features/published/3gp/male_amr122DTX.json
+++ b/data/file_features/published/3gp/male_amr122DTX.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./male_amr122DTX.3gp",
diff --git a/data/file_features/published/3gp/pdin_example.json b/data/file_features/published/3gp/pdin_example.json
index 00e85769..f13e68eb 100644
--- a/data/file_features/published/3gp/pdin_example.json
+++ b/data/file_features/published/3gp/pdin_example.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./pdin_example.3gp",
diff --git a/data/file_features/published/3gp/rs_example_r1.json b/data/file_features/published/3gp/rs_example_r1.json
index c01d0dc9..652882e7 100644
--- a/data/file_features/published/3gp/rs_example_r1.json
+++ b/data/file_features/published/3gp/rs_example_r1.json
@@ -5,12 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": [
-    "video track",
-    "audio track",
-    "Interleaved data",
-    "mp4a sample entry"
-  ],
+  "features": ["Interleaved data", "mp4a sample entry"],
   "notes": "",
   "license": "",
   "rel_filepath": "./rs_example_r1.3gp",
diff --git a/data/file_features/published/isobmff/01_simple.json b/data/file_features/published/isobmff/01_simple.json
index 33d41048..f026deef 100644
--- a/data/file_features/published/isobmff/01_simple.json
+++ b/data/file_features/published/isobmff/01_simple.json
@@ -6,8 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
-    "audio track",
     "Interleaved data",
     "Systems tracks etc.",
     "IOD box",
diff --git a/data/file_features/published/isobmff/02_dref_edts_img.json b/data/file_features/published/isobmff/02_dref_edts_img.json
index 8ccc599d..7aa6bdf9 100644
--- a/data/file_features/published/isobmff/02_dref_edts_img.json
+++ b/data/file_features/published/isobmff/02_dref_edts_img.json
@@ -6,7 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "audio track",
     "image track",
     "data reference to other file",
     "Interleaved data",
diff --git a/data/file_features/published/isobmff/03_hinted.json b/data/file_features/published/isobmff/03_hinted.json
index 45a60a6f..2caad9eb 100644
--- a/data/file_features/published/isobmff/03_hinted.json
+++ b/data/file_features/published/isobmff/03_hinted.json
@@ -6,7 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
     "Interleaved data",
     "RTP hint tracks",
     "hint track setup",
diff --git a/data/file_features/published/isobmff/04_bifs_video.json b/data/file_features/published/isobmff/04_bifs_video.json
index 0c2ecc5d..91475bb4 100644
--- a/data/file_features/published/isobmff/04_bifs_video.json
+++ b/data/file_features/published/isobmff/04_bifs_video.json
@@ -6,7 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
     "data reference to other file",
     "Systems tracks etc.",
     "IOD box",
diff --git a/data/file_features/published/isobmff/05_bifs_video_protected_v2.json b/data/file_features/published/isobmff/05_bifs_video_protected_v2.json
index 0b1a40d4..d013dc0a 100644
--- a/data/file_features/published/isobmff/05_bifs_video_protected_v2.json
+++ b/data/file_features/published/isobmff/05_bifs_video_protected_v2.json
@@ -6,7 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
     "Protected basic",
     "item naming",
     "Systems tracks etc.",
diff --git a/data/file_features/published/isobmff/10_fragments.json b/data/file_features/published/isobmff/10_fragments.json
index ad28c2e8..700585cc 100644
--- a/data/file_features/published/isobmff/10_fragments.json
+++ b/data/file_features/published/isobmff/10_fragments.json
@@ -5,12 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": [
-    "video track",
-    "audio track",
-    "Interleaved data",
-    "multiple mdats"
-  ],
+  "features": ["Interleaved data", "multiple mdats"],
   "notes": "",
   "license": "",
   "rel_filepath": "./10_fragments.mp4",
diff --git a/data/file_features/published/isobmff/14_large.json b/data/file_features/published/isobmff/14_large.json
index 1708d97c..ee5016b3 100644
--- a/data/file_features/published/isobmff/14_large.json
+++ b/data/file_features/published/isobmff/14_large.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["64bit length", "video track", "64bit chunks"],
+  "features": ["64bit length", "64bit chunks"],
   "notes": {
     "compressed": true
   },
diff --git a/data/file_features/published/isobmff/a1-foreman-QCIF.json b/data/file_features/published/isobmff/a1-foreman-QCIF.json
index 99e1de22..85e0b5c5 100644
--- a/data/file_features/published/isobmff/a1-foreman-QCIF.json
+++ b/data/file_features/published/isobmff/a1-foreman-QCIF.json
@@ -6,8 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
-    "audio track",
     "Interleaved data",
     "IOD box",
     "mp4a sample entry",
diff --git a/data/file_features/published/isobmff/a10-foreman_QCIF-raw.json b/data/file_features/published/isobmff/a10-foreman_QCIF-raw.json
index a313be94..8dbdb354 100644
--- a/data/file_features/published/isobmff/a10-foreman_QCIF-raw.json
+++ b/data/file_features/published/isobmff/a10-foreman_QCIF-raw.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "unknown codec type"],
+  "features": ["unknown codec type"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a10-foreman_QCIF-raw.mp4",
diff --git a/data/file_features/published/isobmff/a2-foreman-QCIF-hinted.json b/data/file_features/published/isobmff/a2-foreman-QCIF-hinted.json
index 32614b91..f6e77a0b 100644
--- a/data/file_features/published/isobmff/a2-foreman-QCIF-hinted.json
+++ b/data/file_features/published/isobmff/a2-foreman-QCIF-hinted.json
@@ -6,8 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
-    "audio track",
     "RTP hint tracks",
     "hint track setup",
     "sdp boxes",
diff --git a/data/file_features/published/isobmff/a3-tone-protected.json b/data/file_features/published/isobmff/a3-tone-protected.json
index 4f8aeb2e..e97c815d 100644
--- a/data/file_features/published/isobmff/a3-tone-protected.json
+++ b/data/file_features/published/isobmff/a3-tone-protected.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": ["./a3c-prot-keys.txt"],
-  "features": ["video track", "audio track", "Protected basic", "IOD box"],
+  "features": ["Protected basic", "IOD box"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a3-tone-protected.mp4",
diff --git a/data/file_features/published/isobmff/a3b-tone-deprot.json b/data/file_features/published/isobmff/a3b-tone-deprot.json
index 6bfe1a15..87aab2fc 100644
--- a/data/file_features/published/isobmff/a3b-tone-deprot.json
+++ b/data/file_features/published/isobmff/a3b-tone-deprot.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track", "Protected basic", "IOD box"],
+  "features": ["Protected basic", "IOD box"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a3b-tone-deprot.mp4",
diff --git a/data/file_features/published/isobmff/a4-tone-fragmented.json b/data/file_features/published/isobmff/a4-tone-fragmented.json
index 107b1c91..4036c257 100644
--- a/data/file_features/published/isobmff/a4-tone-fragmented.json
+++ b/data/file_features/published/isobmff/a4-tone-fragmented.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track", "IOD box"],
+  "features": ["IOD box"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a4-tone-fragmented.mp4",
diff --git a/data/file_features/published/isobmff/a5-foreman-AVC.json b/data/file_features/published/isobmff/a5-foreman-AVC.json
index d6e44f9c..2a564e5d 100644
--- a/data/file_features/published/isobmff/a5-foreman-AVC.json
+++ b/data/file_features/published/isobmff/a5-foreman-AVC.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "audio track", "sample dependency"],
+  "features": ["sample dependency"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a5-foreman-AVC.mp4",
diff --git a/data/file_features/published/isobmff/a6_tone_multifile.json b/data/file_features/published/isobmff/a6_tone_multifile.json
index 77a9422e..0bb72dc8 100644
--- a/data/file_features/published/isobmff/a6_tone_multifile.json
+++ b/data/file_features/published/isobmff/a6_tone_multifile.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": ["./myData.dat"],
-  "features": ["video track", "audio track", "data reference to other file"],
+  "features": ["data reference to other file"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a6_tone_multifile.mp4",
diff --git a/data/file_features/published/isobmff/a7-tone-oddities.json b/data/file_features/published/isobmff/a7-tone-oddities.json
index 68357cff..c2745d30 100644
--- a/data/file_features/published/isobmff/a7-tone-oddities.json
+++ b/data/file_features/published/isobmff/a7-tone-oddities.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["implied length", "unknown box", "audio track", "pad bits"],
+  "features": ["implied length", "unknown box", "pad bits"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a7-tone-oddities.mp4",
diff --git a/data/file_features/published/isobmff/a8-foreman_QCIF_edit.json b/data/file_features/published/isobmff/a8-foreman_QCIF_edit.json
index 02c81b20..8aba9a62 100644
--- a/data/file_features/published/isobmff/a8-foreman_QCIF_edit.json
+++ b/data/file_features/published/isobmff/a8-foreman_QCIF_edit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["audio track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./a8-foreman_QCIF_edit.mp4",
diff --git a/data/file_features/published/isobmff/a9-aac-samplegroups-edit.json b/data/file_features/published/isobmff/a9-aac-samplegroups-edit.json
index 2e66e530..53e254e3 100644
--- a/data/file_features/published/isobmff/a9-aac-samplegroups-edit.json
+++ b/data/file_features/published/isobmff/a9-aac-samplegroups-edit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["audio track", "IOD box"],
+  "features": ["IOD box"],
   "notes": "",
   "license": "",
   "rel_filepath": "./a9-aac-samplegroups-edit.mp4",
diff --git a/data/file_features/published/isobmff/f1.json b/data/file_features/published/isobmff/f1.json
index 7c745f8e..a0fd6b55 100644
--- a/data/file_features/published/isobmff/f1.json
+++ b/data/file_features/published/isobmff/f1.json
@@ -5,13 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": [
-    "video track",
-    "audio track",
-    "Interleaved data",
-    "IOD box",
-    "mp4a sample entry"
-  ],
+  "features": ["Interleaved data", "IOD box", "mp4a sample entry"],
   "notes": "",
   "license": "",
   "rel_filepath": "./f1.mp4",
diff --git a/data/file_features/published/isobmff/f2.json b/data/file_features/published/isobmff/f2.json
index 35f462ed..c1f58d7b 100644
--- a/data/file_features/published/isobmff/f2.json
+++ b/data/file_features/published/isobmff/f2.json
@@ -5,13 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": [
-    "video track",
-    "audio track",
-    "Protected basic",
-    "Interleaved data",
-    "IOD box"
-  ],
+  "features": ["Protected basic", "Interleaved data", "IOD box"],
   "notes": "",
   "license": "",
   "rel_filepath": "./f2.mp4",
diff --git a/data/file_features/published/isobmff/fragment-random-access-1+AF8-rev1.json b/data/file_features/published/isobmff/fragment-random-access-1+AF8-rev1.json
index a7a77a4c..bb319bde 100644
--- a/data/file_features/published/isobmff/fragment-random-access-1+AF8-rev1.json
+++ b/data/file_features/published/isobmff/fragment-random-access-1+AF8-rev1.json
@@ -5,12 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": [
-    "video track",
-    "audio track",
-    "mp4a sample entry",
-    "mp4v sample entry"
-  ],
+  "features": ["mp4a sample entry", "mp4v sample entry"],
   "notes": "",
   "license": "",
   "rel_filepath": "./fragment-random-access-1+AF8-rev1.mp4",
diff --git a/data/file_features/published/isobmff/fragment_random_access-2.json b/data/file_features/published/isobmff/fragment_random_access-2.json
index 6ef3c080..98c42cb3 100644
--- a/data/file_features/published/isobmff/fragment_random_access-2.json
+++ b/data/file_features/published/isobmff/fragment_random_access-2.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "mp4v sample entry"],
+  "features": ["mp4v sample entry"],
   "notes": "",
   "license": "",
   "rel_filepath": "./fragment_random_access-2.mp4",
diff --git a/data/file_features/published/isobmff/restricted.json b/data/file_features/published/isobmff/restricted.json
index 276c54ac..7328fdbf 100644
--- a/data/file_features/published/isobmff/restricted.json
+++ b/data/file_features/published/isobmff/restricted.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["late order", "video track"],
+  "features": ["late order"],
   "notes": "",
   "license": "",
   "rel_filepath": "./restricted.mp4",
diff --git a/data/file_features/published/isobmff/rtp_rtcp_reception_hint_tracks_v2.json b/data/file_features/published/isobmff/rtp_rtcp_reception_hint_tracks_v2.json
index 8306be9e..8647d0b6 100644
--- a/data/file_features/published/isobmff/rtp_rtcp_reception_hint_tracks_v2.json
+++ b/data/file_features/published/isobmff/rtp_rtcp_reception_hint_tracks_v2.json
@@ -6,8 +6,6 @@
   "published": true,
   "associated_files": [],
   "features": [
-    "video track",
-    "audio track",
     "hint track setup",
     "sdp boxes",
     "hint stats boxes",
diff --git a/data/file_features/published/isobmff/sg-tl-st.json b/data/file_features/published/isobmff/sg-tl-st.json
index 0d4d9b2f..ab57e729 100644
--- a/data/file_features/published/isobmff/sg-tl-st.json
+++ b/data/file_features/published/isobmff/sg-tl-st.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "layering and subseq grps"],
+  "features": ["layering and subseq grps"],
   "notes": "",
   "license": "",
   "rel_filepath": "./sg-tl-st.mp4",
diff --git a/data/file_features/published/isobmff/timed-metadata.json b/data/file_features/published/isobmff/timed-metadata.json
index a8c70c3c..0bd0e16c 100644
--- a/data/file_features/published/isobmff/timed-metadata.json
+++ b/data/file_features/published/isobmff/timed-metadata.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["metadata track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./timed-metadata.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks.json b/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks.json
index 8affa59d..4989e200 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_multiple_tracks.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks_empty_base.json b/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks_empty_base.json
index 52e44e9b..89e6735e 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks_empty_base.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_multiple_tracks_empty_base.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_multiple_tracks_empty_base.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm.json b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm.json
index 37cc3343..70c46943 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_single_track_nalm.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_all_intra.json b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_all_intra.json
index 9c3758e8..ad4a31a4 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_all_intra.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_all_intra.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_single_track_nalm_all_intra.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_rle.json b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_rle.json
index 31d3313e..8f9f35ea 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_rle.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_nalm_rle.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_single_track_nalm_rle.mp4",
diff --git a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_trif_full_picture.json b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_trif_full_picture.json
index 698991bf..ef26c21e 100644
--- a/data/file_features/published/nalu/hevc/hevc_tiles_single_track_trif_full_picture.json
+++ b/data/file_features/published/nalu/hevc/hevc_tiles_single_track_trif_full_picture.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track"],
+  "features": [],
   "notes": "",
   "license": "",
   "rel_filepath": "./hevc_tiles_single_track_trif_full_picture.mp4",
diff --git a/data/file_features/published/nalu/hevc/hvc2_extractors.json b/data/file_features/published/nalu/hevc/hvc2_extractors.json
index f6a4c55a..8c197cf0 100644
--- a/data/file_features/published/nalu/hevc/hvc2_extractors.json
+++ b/data/file_features/published/nalu/hevc/hvc2_extractors.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors"],
+  "features": ["Extractors"],
   "notes": "",
   "license": "",
   "rel_filepath": "./hvc2_extractors.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hev1_hev2_multiple_tracks_extractors.json b/data/file_features/published/nalu/l-hevc/mhvc_hev1_hev2_multiple_tracks_extractors.json
index 67e59c3f..6dd0bbc7 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hev1_hev2_multiple_tracks_extractors.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hev1_hev2_multiple_tracks_extractors.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hev1_hev2_multiple_tracks_extractors.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hev1_lhe1_multiple_tracks_implicit.json b/data/file_features/published/nalu/l-hevc/mhvc_hev1_lhe1_multiple_tracks_implicit.json
index 12b585e3..e61b9877 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hev1_lhe1_multiple_tracks_implicit.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hev1_lhe1_multiple_tracks_implicit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hev1_lhe1_multiple_tracks_implicit.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hev1_single_track.json b/data/file_features/published/nalu/l-hevc/mhvc_hev1_single_track.json
index 611c3267..95de82e5 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hev1_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hev1_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hev1_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hev2_single_track.json b/data/file_features/published/nalu/l-hevc/mhvc_hev2_single_track.json
index d338b7f7..c6b35934 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hev2_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hev2_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hev2_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_hvc2_multiple_tracks_extractors.json b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_hvc2_multiple_tracks_extractors.json
index 63b0c790..b4727d4c 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_hvc2_multiple_tracks_extractors.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_hvc2_multiple_tracks_extractors.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hvc1_hvc2_multiple_tracks_extractors.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_lhv1_multiple_tracks_implicit.json b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_lhv1_multiple_tracks_implicit.json
index 435d5987..519804d1 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_lhv1_multiple_tracks_implicit.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_lhv1_multiple_tracks_implicit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hvc1_lhv1_multiple_tracks_implicit.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_single_track.json b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_single_track.json
index 46934d7a..a63a9117 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hvc1_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hvc1_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hvc1_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/mhvc_hvc2_single_track.json b/data/file_features/published/nalu/l-hevc/mhvc_hvc2_single_track.json
index 6cc4a0d3..626c4610 100644
--- a/data/file_features/published/nalu/l-hevc/mhvc_hvc2_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/mhvc_hvc2_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./mhvc_hvc2_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hev1_hev2_multiple_tracks_extractors.json b/data/file_features/published/nalu/l-hevc/shvc_hev1_hev2_multiple_tracks_extractors.json
index a2603c8c..097b676f 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hev1_hev2_multiple_tracks_extractors.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hev1_hev2_multiple_tracks_extractors.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hev1_hev2_multiple_tracks_extractors.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hev1_lhe1_multiple_tracks_implicit.json b/data/file_features/published/nalu/l-hevc/shvc_hev1_lhe1_multiple_tracks_implicit.json
index 34d9ad83..24719ca2 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hev1_lhe1_multiple_tracks_implicit.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hev1_lhe1_multiple_tracks_implicit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hev1_lhe1_multiple_tracks_implicit.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hev1_single_track.json b/data/file_features/published/nalu/l-hevc/shvc_hev1_single_track.json
index 14e546ad..c6b855fc 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hev1_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hev1_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hev1_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hev2_single_track.json b/data/file_features/published/nalu/l-hevc/shvc_hev2_single_track.json
index b6a6109f..47d5cc04 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hev2_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hev2_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hev2_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hvc1_hvc2_multiple_tracks_extractors.json b/data/file_features/published/nalu/l-hevc/shvc_hvc1_hvc2_multiple_tracks_extractors.json
index 03bc26ac..bc6400f6 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hvc1_hvc2_multiple_tracks_extractors.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hvc1_hvc2_multiple_tracks_extractors.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hvc1_hvc2_multiple_tracks_extractors.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hvc1_lhv1_multiple_tracks_implicit.json b/data/file_features/published/nalu/l-hevc/shvc_hvc1_lhv1_multiple_tracks_implicit.json
index f39423f1..997d6b18 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hvc1_lhv1_multiple_tracks_implicit.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hvc1_lhv1_multiple_tracks_implicit.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hvc1_lhv1_multiple_tracks_implicit.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hvc1_single_track.json b/data/file_features/published/nalu/l-hevc/shvc_hvc1_single_track.json
index bd3bcee9..6e247735 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hvc1_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hvc1_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hvc1_single_track.mp4",
diff --git a/data/file_features/published/nalu/l-hevc/shvc_hvc2_single_track.json b/data/file_features/published/nalu/l-hevc/shvc_hvc2_single_track.json
index 5963f916..7bb78c17 100644
--- a/data/file_features/published/nalu/l-hevc/shvc_hvc2_single_track.json
+++ b/data/file_features/published/nalu/l-hevc/shvc_hvc2_single_track.json
@@ -5,7 +5,7 @@
   "version": 1,
   "published": true,
   "associated_files": [],
-  "features": ["video track", "Extractors", "Implicit Reconstruction"],
+  "features": ["Extractors", "Implicit Reconstruction"],
   "notes": "",
   "license": "",
   "rel_filepath": "./shvc_hvc2_single_track.mp4",
diff --git a/data/schemas/standard.schema.json b/data/schemas/standard.schema.json
index 3c900956..9f398262 100644
--- a/data/schemas/standard.schema.json
+++ b/data/schemas/standard.schema.json
@@ -51,7 +51,13 @@
             "description": "All the possible containers for this entry. If the element is a string then it is treated as fourcc or type. Otherwise if an object is provided then the only key in it will be treated as type and the items in that array will be treated as fourccs. The latter form will be used to differentiate between different types of containers that have the same fourcc."
           },
           "syntax": {
-            "type": "string",
+            "oneOf": [
+              {
+                "type": "string",
+                "minLength": 1
+              },
+              { "type": "null" }
+            ],
             "description": "The full syntax of this entry, as specified in the standard."
           },
           "versions": {
diff --git a/data/standard_features/14496-12/boxes.json b/data/standard_features/14496-12/boxes.json
index 2bc3c70a..b3617aee 100644
--- a/data/standard_features/14496-12/boxes.json
+++ b/data/standard_features/14496-12/boxes.json
@@ -457,7 +457,7 @@
     {
       "fourcc": "iprp",
       "description": "Item Properties Box",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "Box",
       "syntax": "aligned(8) class ItemPropertiesBox\n\t\textends Box('iprp') {\n\tItemPropertyContainerBox property_container;\n\tItemPropertyAssociationBox association[];\n }"
     },
@@ -473,7 +473,7 @@
     {
       "fourcc": "bxml",
       "description": "binary XML container",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0],
       "flags": [],
@@ -529,7 +529,7 @@
     {
       "fourcc": "dinf",
       "description": "data information box, container",
-      "containers": ["minf", "meta"],
+      "containers": [{ "FullBox": ["meta"] }, "minf"],
       "type": "Box",
       "syntax": "aligned(8) class DataInformationBox extends Box('dinf') {\n}"
     },
@@ -590,7 +590,7 @@
     {
       "fourcc": "fiin",
       "description": "FD Item Information",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "Box",
       "syntax": "aligned(8) class PartitionEntry extends Box('paen') {\n\tFilePartitionBox\tblocks_and_symbols;\n\tFECReservoirBox\tFEC_symbol_locations; //optional\n\tFileReservoirBox\tFile_symbol_locations; //optional\n}\n\naligned(8) class FDItemInformationBox\n\t\textends FullBox('fiin', version = 0, 0) {\n\tunsigned int(16)\tentry_count;\n\tPartitionEntry\t\tpartition_entries[ entry_count ];\n\tFDSessionGroupBox\tsession_info;\t\t\t//optional\n\tGroupIdToNameBox\tgroup_id_to_name;\t//optional\n}"
     },
@@ -645,14 +645,14 @@
     {
       "fourcc": "grpl",
       "description": "Groups list box",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "Box",
       "syntax": "aligned(8) class GroupsListBox extends Box('grpl') {\n}"
     },
     {
       "fourcc": "hdlr",
       "description": "handler, declares the media (handler) type",
-      "containers": ["mdia", "meta", "minf"],
+      "containers": [{ "FullBox": ["meta"] }, "mdia", "minf"],
       "type": "FullBox",
       "versions": [0],
       "flags": [],
@@ -670,14 +670,14 @@
     {
       "fourcc": "idat",
       "description": "Item data",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "Box",
       "syntax": "aligned(8) class ItemDataBox extends Box('idat') {\n\tbit(8) data[];\n}"
     },
     {
       "fourcc": "iinf",
       "description": "item information",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0, 1],
       "flags": [],
@@ -688,7 +688,7 @@
       "description": "item location box",
       "versions": [0, 1, 2],
       "flags": [],
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "syntax": "aligned(8) class ItemLocationBox extends FullBox('iloc', version, 0) {\n\tunsigned int(4)\toffset_size;\n\tunsigned int(4)\tlength_size;\n\tunsigned int(4)\tbase_offset_size;\n\tif ((version == 1) || (version == 2)) {\n\t\tunsigned int(4)\tindex_size;\n\t} else {\n\t\tunsigned int(4)\treserved;\n\t}\n\tif (version < 2) {\n\t\tunsigned int(16)\titem_count;\n\t} else if (version == 2) {\n\t\tunsigned int(32)\titem_count;\n\t}\n\tfor (i=0; i<item_count; i++) {\n\t\tif (version < 2) {\n\t\t\tunsigned int(16)\titem_ID;\n\t\t} else if (version == 2) {\n\t\t\tunsigned int(32)\titem_ID;\n\t\t}\n\t\tif ((version == 1) || (version == 2)) {\n\t\t\tunsigned int(12)\treserved = 0;\n\t\t\tunsigned int(4)\tconstruction_method;\n\t\t}\n\t\tunsigned int(16)\tdata_reference_index;\n\t\tunsigned int(base_offset_size*8)\tbase_offset;\n\t\tunsigned int(16)\t\textent_count;\n\t\tfor (j=0; j<extent_count; j++) {\n\t\t\tif (((version == 1) || (version == 2)) && (index_size > 0)) {\n\t\t\t\tunsigned int(index_size*8)\titem_reference_index;\n\t\t\t}\n\t\t\tunsigned int(offset_size*8)\textent_offset;\n\t\t\tunsigned int(length_size*8)\textent_length;\n\t\t}\n\t}\n}"
     },
@@ -717,7 +717,7 @@
     {
       "fourcc": "ipro",
       "description": "item protection",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0],
       "flags": [],
@@ -728,7 +728,7 @@
       "description": "Item reference box",
       "versions": [0, 1],
       "flags": [],
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "syntax": "aligned(8) class ItemReferenceBox extends FullBox('iref', version, 0) {\n\tif (version==0) {\n\t\tSingleItemTypeReferenceBox\t\t\t\treferences[];\n\t} else if (version==1) {\n\t\tSingleItemTypeReferenceBoxLarge\treferences[];\n\t}\n}"
     },
@@ -888,7 +888,7 @@
     {
       "fourcc": "pitm",
       "description": "primary item reference",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0, 1],
       "flags": [],
@@ -1428,7 +1428,7 @@
     {
       "fourcc": "xml ",
       "description": "XML container",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0],
       "flags": [],
diff --git a/data/standard_features/14496-12/codecs.json b/data/standard_features/14496-12/codecs.json
index bc2bdcfa..b19173b8 100644
--- a/data/standard_features/14496-12/codecs.json
+++ b/data/standard_features/14496-12/codecs.json
@@ -42,7 +42,7 @@
       "description": "Encrypted Text",
       "type": "PlainTextSampleEntry",
       "containers": ["stsd"],
-      "syntax": ""
+      "syntax": null
     },
     {
       "fourcc": "encv",
@@ -168,7 +168,7 @@
       "description": "SRTCP reception hint track",
       "type": "HintSampleEntry",
       "containers": ["stsd"],
-      "syntax": ""
+      "syntax": null
     },
     {
       "fourcc": "stpp",
@@ -189,7 +189,7 @@
       "description": "Encrypted/Protected subtitles",
       "type": "PlainTextSampleEntry",
       "containers": ["stsd"],
-      "syntax": ""
+      "syntax": null
     },
     {
       "fourcc": "encp",
diff --git a/data/standard_features/14496-12/handlers.json b/data/standard_features/14496-12/handlers.json
new file mode 100644
index 00000000..c48bb3f1
--- /dev/null
+++ b/data/standard_features/14496-12/handlers.json
@@ -0,0 +1,83 @@
+{
+  "name": "Handlers",
+  "description": "Handler types defined in ISOBMFF",
+  "entries": [
+    {
+      "fourcc": "auxv",
+      "description": "Auxiliary video",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "hint",
+      "description": "Hint",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "meta",
+      "description": "Metadata",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "mp7b",
+      "description": "MPEG-7 (binary meta-data)",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "mp7t",
+      "description": "MPEG-7 (textual meta-data)",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "null",
+      "description": "No handling required (meta-data)",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "soun",
+      "description": "Audio",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "subt",
+      "description": "Subtitles",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "vide",
+      "description": "Video",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "volv",
+      "description": "Volumetric visual media",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    },
+    {
+      "fourcc": "hapt",
+      "description": "Haptics",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    }
+  ]
+}
diff --git a/data/standard_features/14496-12/user_defined.json b/data/standard_features/14496-12/user_defined.json
index 4ec8554c..65c8744c 100644
--- a/data/standard_features/14496-12/user_defined.json
+++ b/data/standard_features/14496-12/user_defined.json
@@ -3,13 +3,7 @@
   "64bit headers": "There are 64-bit versions of the movie, track, and media headers, that allow long durations and dates after 2040.",
   "64bit chunks": "The 64-bit version of the chunk offset table is used, and the chunk offsets have non-zero bits in their upper 32 bits.",
   "64bit fragments": "Fragments are used in combination with 64-bit offsets",
-  "video track": "There is a video track with video headers",
-  "audio track": "There is an audio track with audio headers",
-  "metadata track": "A timed metadata (or multiplexed timed metadata) track",
-  "volumetric track": "There is a volumetric video track",
-  "haptic track": "There is a haptic track",
   "image track": "(no sync table) A track with a single image in it.",
-  "hint track": "This section tests hint tracks.",
   "RTP hint tracks": "Regular RTP hint tracks are present. They should be ignored for local playback.",
   "implied length": "(size=0) Box with the length running to end of file (last box)",
   "unknown box": "A box with an 'unknown' code is present in the file and should be ignored. The box type used for testing could be one of 'junk', 'mess', etc.",
diff --git a/data/standard_features/23008-12/boxes.json b/data/standard_features/23008-12/boxes.json
index a0c2bf06..8bc6ac02 100644
--- a/data/standard_features/23008-12/boxes.json
+++ b/data/standard_features/23008-12/boxes.json
@@ -21,7 +21,7 @@
     {
       "fourcc": "md5i",
       "description": "MD5IntegrityBox",
-      "containers": ["meta"],
+      "containers": [{ "FullBox": ["meta"] }],
       "type": "FullBox",
       "versions": [0],
       "flags": [],
diff --git a/data/standard_features/23008-12/handlers.json b/data/standard_features/23008-12/handlers.json
new file mode 100644
index 00000000..67cf3986
--- /dev/null
+++ b/data/standard_features/23008-12/handlers.json
@@ -0,0 +1,13 @@
+{
+  "name": "Handlers",
+  "description": "Handler types defined in HEIF",
+  "entries": [
+    {
+      "fourcc": "pict",
+      "description": "Image Item and Image sequences",
+      "containers": ["hdlr"],
+      "type": "handler_type",
+      "syntax": null
+    }
+  ]
+}
diff --git a/src/construct/boxes.py b/src/construct/boxes.py
index ff15102e..a9c11f61 100644
--- a/src/construct/boxes.py
+++ b/src/construct/boxes.py
@@ -178,6 +178,8 @@ def main():
     syntaxes = set()
     for value in BOXES.values():
         for _box in value:
+            if _box.syntax is None:
+                continue
             matches = extract_syntax.findall(_box.syntax)
             for match in matches:
                 syntaxes.add(match)
diff --git a/src/construct/files.py b/src/construct/files.py
index 983097d9..2ea8442a 100644
--- a/src/construct/files.py
+++ b/src/construct/files.py
@@ -77,6 +77,11 @@ def crawl(hierarchy, path=[]):
                     sg_entry = {"@Type": value["@grouping_type"]}
                     add_variant(add, sg_entry, path + [fourcc])
 
+                # Special case for handlers
+                if "@hdlrType" in value:
+                    hdlr_entry = {"@Type": value["@hdlrType"]}
+                    add_variant(add, hdlr_entry, path + [fourcc])
+
                 add_variant(add, value, path)
                 crawl(value, path + [fourcc])
             elif isinstance(value, list):