-Each string gives a human-readable description of the key and the
-first line of documentation for the bound function."
+Each string gives a human-readable description of the key and a
+one-line description of the bound function. See `notmuch-help'
+for an overview of how this documentation is extracted.
+
+UA-KEYS should be a key sequence bound to `universal-argument'.
+It will be used to describe bindings of commands that support a
+prefix argument. PREFIX and TAIL are used internally."