diff --git a/user-dirs/.config/user-dirs.dirs b/user-dirs/.config/user-dirs.dirs
index 6ea9c67..32218de 100644
--- a/user-dirs/.config/user-dirs.dirs
+++ b/user-dirs/.config/user-dirs.dirs
@@ -1,3 +1,10 @@
+# This file is written by xdg-user-dirs-update
+# If you want to change or add directories, just edit the line you're
+# interested in. All local changes will be retained on the next run.
+# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
+# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
+# absolute path. No other format is supported.
+#
 XDG_DESKTOP_DIR="$HOME/.desk"
 XDG_DOCUMENTS_DIR="$HOME/doc"
 XDG_DOWLOAD_DIR="$HOME/down"