Make sure our bundled WebExtensions are running in Private Browsing Mode

We might need to flip a pref to allow our bundled WebExtensions to run in Private Browsing Mode starting with ESR 68. See:

https://bugzilla.mozilla.org/show_bug.cgi?id=1511636 https://bugzilla.mozilla.org/show_bug.cgi?id=1457001

for context.

added TorBrowserTeam201908R component::applications/tor browser ff68-esr owner::tbb-team priority::medium resolution::fixed severity::normal sponsor::44-can status::closed type::task labels

#29192 (moved) is a duplicate.

Setting extensions.allowPrivateBrowsingByDefault = true should do it: https://github.com/acatarineu/tor-browser/commit/28896.

Adding Sponsor 44 to ESR68 tickets

Trac:
Sponsor: N/A to Sponsor44-can

Trac:
Status: new to needs_review
Keywords: ff68-esr deleted, ff68-esr TorBrowserTeam201908R added

I actually think we are good for our own extensions. System extensions are good by default it seems and extensions already running/being shipped with are getting whitelisted during migration (see the resulting extensions.webextensions.ExtensionStorageIDB.migrated.https-everywhere-eff@eff.org etc.). Thus I think this is cool for getting extension updates as well. That is: updates whitelisted won't break if never versions are up for download.

There is the rest risk of Mozilla messing this up vs. better protection against random extensions in Tor's default mode. Right now, I am leaning towards following Mozilla's defaults, though, just doing #31555 (moved). Thoughts?

Trac:
Cc: N/A to tbb-team
Status: needs_review to needs_information

Some additional reading material is over at: https://support.mozilla.org/en-US/kb/extensions-private-browsing.

Not completely sure about this one.

What I had thought was: by default in Tor Browser we only have private windows, so it makes sense to always enable extensions. Otherwise from the user perspective it will be broken behaviour: they might install an extension and see no change (icons, etc.), then maybe file bugs.

It may work as a protection against something that we don't support: installing extensions others than the shipped ones. But, at the end of the day, we do not forbid installing extensions either, so this change might be surprising for users.

Replying to acat:

Not completely sure about this one.

What I had thought was: by default in Tor Browser we only have private windows, so it makes sense to always enable extensions. Otherwise from the user perspective it will be broken behaviour: they might install an extension and see no change (icons, etc.), then maybe file bugs.

It may work as a protection against something that we don't support: installing extensions others than the shipped ones. But, at the end of the day, we do not forbid installing extensions either, so this change might be surprising for users.

Okay, that's not unreasonable. After all the users might not know (and should not need to know) that they are in a special mode. They just want to have a working browser and installing extensions is surely working without issues in a vanilla Firefox, right? Let's take your patch then. We can revisit that decision later on if needed. Cherry-picked onto tor-browser-68.1.0esr-9.0-1 (commit 8aabfb8128a8125a00d0a36d41518379258e0b38).

Trac:
Status: needs_information to closed
Resolution: N/A to fixed

https://bugzilla.mozilla.org/show_bug.cgi?id=1566000#c1

closed

mentioned in issue #29192 (moved)

mentioned in issue #30429 (moved)

mentioned in issue #31555 (moved)

moved to tpo/applications/tor-browser#28896 (closed)