Variable: version-control
version-control is a customizable variable defined in files.el.gz.
Value
nil
Documentation
Control use of version-numbered backup files.
When t, make numbered backup files unconditionally.
When nil, make them for files that already have numbered backups.
The value never means never make numbered backups.
Probably introduced at or before Emacs version 17.
Source Code
;; Defined in /usr/src/emacs/lisp/files.el.gz
(defcustom version-control nil
"Control use of version-numbered backup files.
When t, make numbered backup files unconditionally.
When nil, make them for files that already have numbered backups.
The value `never' means never make numbered backups."
:type '(choice (const :tag "Never" never)
(const :tag "If numbered backups exist" nil)
(other :tag "Always" t))
:safe #'version-control-safe-local-p
:group 'backup)