diff --git a/modules/history-substring-search/init.zsh b/modules/history-substring-search/init.zsh
index 1146b7b..4c944d7 100644
--- a/modules/history-substring-search/init.zsh
+++ b/modules/history-substring-search/init.zsh
@@ -9,6 +9,7 @@
 # Load dependencies.
 omodload 'editor'
 
+# Source module files.
 source "${0:h}/external/zsh-history-substring-search.zsh"
 
 #
diff --git a/modules/syntax-highlighting/init.zsh b/modules/syntax-highlighting/init.zsh
index d57920c..d988b58 100644
--- a/modules/syntax-highlighting/init.zsh
+++ b/modules/syntax-highlighting/init.zsh
@@ -10,6 +10,7 @@ if ! zstyle -t ':omz:module:syntax-highlighting' color; then
   return 1
 fi
 
+# Source module files.
 source "${0:h}/external/zsh-syntax-highlighting.zsh"
 
 # Set the highlighters.