RE: how to prevent font-lock from messing with a portion of text?

[Drew Adams]

> Sorry, I was a bit unclear. You can not be sure
> font-lock-default-fontify-region is called. That depends on the setting
> of font-lock-fontify-region-function. (And if this frame-work is used
> for the fontifying.)
> I guess if it is then your method might work.

If the default fontify function is not used, then someone wants a
non-default behavior. AFAIK, there is no way to know whether that desired
behavior should respect `font-lock-ignore'. Mind-reading is not scheduled
for addition before Emacs 27, AFAIK ;-).

This seems similar to the MATCHER question. If `font-lock-ignore' or
equivalent is added to Emacs, then this would need to be documented, so
users understand it. IOW, `font-lock-ignore' is respected only by default
fontifying and default unfontifying.