/e/ OS per default comes with the PDF reader PDF Viewer Plus. This App is about 2 years old and F-Droid states that it has known vulnerabilities.
https://f-droid.org/de/packages/com.gsnathan.pdfviewer/
Yes, and yes.
Thanks as always for your fast and competent replies. (Interestingly enough not even the topic suggestions didn’t show this thread, after I entered my title, but showed a view, which didn’t even have PDF Viewer Plus in the title.)
https://community.e.foundation/search?q=pdf%20viewer%20plus, 6th hit for me .
I guess I checked the wrong places to closely.
https://gitlab.e.foundation/search?scope=merge_requests&search=pdf+viewer+plus