diff --git a/Docker/github_ci_dockerfile b/Docker/github_ci_dockerfile
index 64064296..d86c9443 100644
--- a/Docker/github_ci_dockerfile
+++ b/Docker/github_ci_dockerfile
@@ -54,6 +54,8 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
       apt-get autoclean -y && \
       rm -rf /var/cache/apt/* /var/lib/apt/lists/*
 
+# linkify-it-py (required by sphinx doc build) is not available in Ubuntu 22.04 as package
+# the following manually installs it and its only dependency micro-py
 RUN mkdir -p /src && cd /src \
  && curl -LOOO http://archive.ubuntu.com/ubuntu/pool/universe/u/uc-micro-py/uc-micro-py_1.0.1{-3.dsc,.orig.tar.xz,-3.debian.tar.xz} \
  && dpkg-source -x uc-micro-py_1.0.1-3.dsc \
diff --git a/Docker/openmpi_dockerfile b/Docker/openmpi_dockerfile
index bdedcd36..9b7c99a5 100644
--- a/Docker/openmpi_dockerfile
+++ b/Docker/openmpi_dockerfile
@@ -67,6 +67,8 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-ins
       apt-get autoclean -y && \
       rm -rf /var/cache/apt/* /var/lib/apt/lists/*
 
+# linkify-it-py (required by sphinx doc build) is not available in Ubuntu 22.04 as package
+# the following manually installs it and its only dependency micro-py
 RUN mkdir -p /src && cd /src \
  && curl -LOOO http://archive.ubuntu.com/ubuntu/pool/universe/u/uc-micro-py/uc-micro-py_1.0.1{-3.dsc,.orig.tar.xz,-3.debian.tar.xz} \
  && dpkg-source -x uc-micro-py_1.0.1-3.dsc \