How come Android doesn't have a built in PDF viewer?
Forgive me for this stupid question. I just transitioned from iPhone to Pixel (GrapheneOS) and I'm curious why there isn't a built in PDF viewer like on iPhone? It feels like you have to open things externally pretty often, but I figure there's a reason for that. I haven't used Android in many years and I recently developed an interest for the technical aspects of things, so again, do forgive this beginners question.
Pdf has a mind-bogging array of features, which make it so entrenched in the corporate world with no viable replacements at the moment. Things like forms where users can fill them out and submit (surprisingly a popular feature), cryptographic signing to prevent tampering, DRM, etc. Heck, I think you can even add JavaScript code to a pdf.