Landing in 66: force opt-in to run extensions in private browsing

Shane Caraveo scaraveo at
Tue Dec 18 15:39:49 UTC 2018

This is an FYI so you don't get surprised in the near future.

The extensions API includes support for an "incognito" entry in the 
extension manifest where an extension may opt-out of running in private 
browsing windows.  Chrome has since made that the default, and requires 
an opt-in by the user to run an extension in private browsing.  We're 
playing a bit of followup on this, since we bypassed the feature during 
the crazy ramp-up for webextensions.

The intention is to land this for 66, and a large chunk of it landed the 
other day.  Extensions currently cannot make use of what has landed 
(though tests can and do).  Extensions will continue to work as they 
previously did until we pref the feature on.

The next part to land will be additional UI in about:addons[1] that 
allows the user to enable an extension for private browsing.  A pref 
(off for now) will be introduced to enable this.  At that point, you 
will be able to play with it, however there is more work to be done at 
the webextension API level.  The pref will not be turned on until all 
necessary API modifications are completed.

Assuming that everything goes according to plan, you will see this 
pref'd on during the 66 nightly cycle.  At that point, all of your 
extensions, excluding system extensions, will stop working in private 
browsing until you enable those you want to work there.

If you are curious you can look through the meta bug[2].  If you have 
questions, please feel free to reach out to me, mixedpuppy, on 
#webextensions irc channel or #add-ons on slack.


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