In my config file, I set properties for some faces used by my setup of Doom Emacs. These properties are promptly ignored when Emacs is loaded, and what I see is how things were before. I'm guessing that Doom overwrites my changes—however, seeing as it's rather big, I'd prefer to not leaf through its code in search of these faces, and instead have Emacs tell me when they're changed like it can do with variables via
debug-on-variable-change. But, faces aren't variables,
debug-on-variable-change doesn't work on them, and I don't see a
Is there a ‘watch for changes’ facility for faces?
emacs -Q(no init file). Then bisect your init file (1/2, 1/4, 1/8,...) to locate the problem.
M-x debug-on-entry, or set breakpoints to the debugger anywhere you like, by inserting
(debug)where you want to enter the debugger.