Believe it or not, the Nikelodeon Teenage Mutant Ninja Turtles show some fun Star Trek stuff in it. Leonardo's favorite show is called Space Heroes, which is a parody of Star Trek: The Animated Series.
In this case, "PDF file" is a homophone for "pedophile".
For me, it's not image viewers, but websites that take photo uploads. None of them that I've ever used have supported webp, so I always have to convert to png or jpg.
I wholeheartedly agree. I'm a technical person, I run Linux as my primary OS and use FOSS software. But I also have a full time job and 2 small kids, and frankly I just don't have the time or patience to be a full time sysadmin. Proton has come a long way in providing alternatives to Gmail, GCalendar, GDrive, etc., but like you said if you want to replace ALL of Google you practically have to self host a gazillion Nextcloud instances or whatever.
I found that even with AdGuard DNS enabled, I still saw promoted posts (ads) using the Reddit app, so I deleted it.
Chuds