vc-version-backup-file-name

vc-version-backup-file-name is a compiled Lisp function in `vc-hooks.el'.

(vc-version-backup-file-name FILE &optional REV MANUAL REGEXP)

Return a backup file name for REV or the current version of FILE.
If MANUAL is non-nil it means that a name for backups created by
the user should be returned; if REGEXP is non-nil that means to return
a regexp for matching all such backup files, regardless of the version.