-The optional QUERY-CONTEXT is a notmuch search term. Only messages from the thread
-matching this search term are shown if non-nil. "
+The optional QUERY-CONTEXT is a notmuch search term. Only
+messages from the thread matching this search term are shown if
+non-nil.
+
+The optional BUFFER-NAME provides the name of the buffer in which
+the message thread is shown. If it is nil (which occurs when the
+command is called interactively) the argument to the function is
+used."