;; default implementation always returns nil.
;;
;; - root (file)
-;;
+;;
;; Return the root of the VC controlled hierarchy for file.
;;
;; - repository-hostname (dirname)
;; from ignored files.
;; When called from Lisp code, if DIRECTORY is non-nil, the
;; repository to use will be deduced by DIRECTORY.
-;;
+;;
;; - ignore-completion-table
-;;
-;; Return the completion table for files ignored by the version
-;; control system in `default-directory'.
-;;
+;;
+;; Return the completion table for files ignored by the current
+;; version control system, e.g., the entries in `.gitignore' and
+;; `.bzrignore'.
+;;
;; - previous-revision (file rev)
;;
;; Return the revision number that precedes REV for FILE, or nil if no such