Just a minor nitpick I noticed during updates:

gnome-browser-connector suggests firefox (which is only in unstable),
but not firefox-esr (which is in testing/stable). So this dependency is
not solvable in Debian testing/stable.

AIUI firefox-esr integrates with Gnome shell if gnome-browser-connector
is installed and the (not packaged) firefox add-on "GNOME Shell
integration" is installed.

Please change this dependency to

Suggests: firefox-esr | firefox