Variable: text-scale-remap-header-line
text-scale-remap-header-line is a buffer-local variable defined in
face-remap.el.gz.
Documentation
If non-nil, text scaling may change font size of header lines too.
Probably introduced at or before Emacs version 28.1.
Source Code
;; Defined in /usr/src/emacs/lisp/face-remap.el.gz
(defvar-local text-scale-remap-header-line nil
"If non-nil, text scaling may change font size of header lines too.")