The PDF is now standardized as ISO 32000, it's open for everyone to create compatible tools.
Re:SumatraPDF Reader
by looperhacks on Tuesday October 24, 2023 @05:40AM
(#37996746)
"Open" for the cheap price of ~$230
Re:SumatraPDF Reader
by SV_BubbleTime on Tuesday October 24, 2023 @11:17AM
(#38000378)
I deal with ISO all the time, they’re cutting you a “deal” there.
Even worse PDF is not "open source", it should have been accompanied by LaTeX source.