vc-default-ignore

vc-default-ignore is a compiled Lisp function in `vc.el'.

(vc-default-ignore BACKEND FILE &optional DIRECTORY REMOVE)

Ignore FILE under the VCS of DIRECTORY (default is `default-directory').
FILE is a file wildcard, relative to the root directory of DIRECTORY.
When called from Lisp code, if DIRECTORY is non-nil, the
repository to use will be deduced by DIRECTORY; if REMOVE is
non-nil, remove FILE from ignored files.
Argument BACKEND is the backend you are using.