Variable: emacs-build-time
emacs-build-time is a variable defined in version.el.gz.
Value
nil
Documentation
Time at which Emacs was dumped out, or nil if not available.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/version.el.gz
(defconst emacs-build-time (if emacs-build-system (current-time))
"Time at which Emacs was dumped out, or nil if not available.")