With firefox from snap on a freshly installed Ubuntu 22.04, the browser does not know any application to open a pdf.
I have configured 'always ask' and get the dialogs shown below when clicking on a pdf. Since evince and qpdfview are installed, they should appear in the 'Select Application' dialog.
Question: Can anyone explain where firefox learns which applications are available and how this can be fixed?
While this answer discusses possibilities to get evince to work in firefox, I am interested in the more fundamental question of how firefox learns which applications may be used to open what?
Further snap firefox apparmor profiles are probably related. In /var/lib/snapd/apparmor/profiles
there are 7 files with firefox
in the name, totaling 11953 lines. :-/
Please don't get distracted by 'localhost' and 'http' as the pdf source. The same happens with downloads from public site with https and valid certificates.
evince
shown as one option and cannot even configure it to be used in firefox settings. – Harald Jan 14 '23 at 07:48