I think there is some issue with licensing from Adobe on this. Someone who knows more than me might educate us.
The standards related to PDF are open. https://en.wikipedia.org/wiki/PDF : ”PDF was standardized as an open format, ISO 32000, in 2008, and no longer requires any royalties for its implementation” Also, https://en.wikipedia.org/wiki/PDF#Intellectual_property : ”Anyone may create applications that can read and write PDF files without having to pay royalties to Adobe Systems; Adobe holds patents to PDF, but licenses th…
and half a dozen image formats, font formats, bits of PostScript, I think there is even some XML lurking in there.