diff --git a/share/functions/__fish_complete_extensions.fish b/share/functions/__fish_complete_extensions.fish
index f39adb6ff..c7a1d5aa6 100644
--- a/share/functions/__fish_complete_extensions.fish
+++ b/share/functions/__fish_complete_extensions.fish
@@ -1,3 +1,5 @@
+# Usage: __fish_complete_extensions extension1 extension2 ...
+# Example: __fish_complete_extensions png jpg
 function __fish_complete_extensions \
     --description 'Suggest provided extensions as $argv if the current token ends with a dot'