Let's track this as https://bugzilla.redhat.com/show_bug.cgi?id=1908018 as update system isn't suitable for it.
I rebuilt Firefox 84 with in-tree nss and it works a expected. With nss-3.59 from this update the add-ons are broken.
I'll test that.
FEDORA-2020-99834af551 is needed for this update.
Please also give karma to FEDORA-2020-beaae4e3c1 which is needed for this update. Thanks.
Okay, let's improve that for further releases.
I added dbus-glib as a dependency to firefox-85.0-5