User stylesheet is broken when not running in flatpak
Probably my fault:
** (epiphany:44839): WARNING **: 11:19:48.055: No available application to open /tmp/epiphany-mcatanzaro-FTs9wx/epiphany/user-stylesheet.css: Error when getting information for file “/tmp/epiphany-mcatanzaro-FTs9wx/epiphany/user-stylesheet.css”: No such file or directory