argument (the directory) and should return either nil to mean
that it is not applicable, or a project instance.")
-;; FIXME: Using the current approach, we don't have access to the
-;; "library roots" of language A from buffers of language B, which
+;; FIXME: Using the current approach, major modes are supposed to set
+;; this variable to a buffer-local value. So we don't have access to
+;; the "library roots" of language A from buffers of language B, which
;; seems desirable in multi-language projects, at least for some
;; potential uses, like "jump to a file in project or library".
;;