Re:Embedded PDF viewer in Firefox 81 supports filling forms
by BHSPitMonkey on Tuesday September 22, 2020 @05:53PM
(#24560398)
Debian actually goes out of their way to patch those checks out in their PDF-related packages as part of their stance against DRM, like this example with "pdftk":
https://sources.debian.org/patches/pdftk/2.02-4/drm_fix/