1895020 - Broken `firefox.cfg` autoconfig file can break background task startup

Status: NEW

(Firefox :: Installer, defect, P3)

Description

[Nick Alexander :nalexander [he/him]]

Per https://bugzilla.mozilla.org/show_bug.cgi?id=1858090#c17, it's possible that errors in firefox.cfg (see around https://searchfox.org/mozilla-central/rev/38377227b8f96fda8f418db614e6a8aa67d01c31/modules/libpref/Preferences.cpp#3706-3711) may cause background tasks to fail. If configuration errors can impact background tasks, it's possible they impact regular Firefox startup as well. This ticket tracks running this down: is there an issue? If so, let's address it.