Variable: before-make-frame-hook
before-make-frame-hook is a variable defined in frame.el.gz.
Value
nil
Documentation
Functions to run before make-frame creates a new frame.
Note that these functions are usually not run for the initial frame, unless you add them to the hook in your early-init file.
Probably introduced at or before Emacs version 19.20.
Source Code
;; Defined in /usr/src/emacs/lisp/frame.el.gz
(defvar before-make-frame-hook nil
"Functions to run before `make-frame' creates a new frame.
Note that these functions are usually not run for the initial
frame, unless you add them to the hook in your early-init file.")