diff --git a/reference/intl/constants.xml b/reference/intl/constants.xml
index bd803d908a52..5aa04e32c243 100644
--- a/reference/intl/constants.xml
+++ b/reference/intl/constants.xml
@@ -148,6 +148,39 @@
      </simpara>
     </listitem>
    </varlistentry>
+   <varlistentry xml:id="constant.grapheme-extr-count">
+    <term>
+     <constant>GRAPHEME_EXTR_COUNT</constant>
+     (<type>int</type>)
+    </term>
+    <listitem>
+     <simpara>
+      The number of default grapheme clusters to extract.
+     </simpara>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="constant.grapheme-extr-maxbytes">
+    <term>
+     <constant>GRAPHEME_EXTR_MAXBYTES</constant>
+     (<type>int</type>)
+    </term>
+    <listitem>
+     <simpara>
+      The maximum number of bytes returned.
+     </simpara>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="constant.grapheme-extr-maxchars">
+    <term>
+     <constant>GRAPHEME_EXTR_MAXCHARS</constant>
+     (<type>int</type>)
+    </term>
+    <listitem>
+     <simpara>
+      The maximum number of UTF-8 characters returned.
+     </simpara>
+    </listitem>
+   </varlistentry>
   </variablelist>
   <variablelist xml:id="constant.idna-errors">
    <para>