Firefox Removing Support for Unpacked Extensions

(Mike Conca) #1

With the release of Firefox 62 (currently scheduled for August 21, 2018) Mozilla will discontinue support for unpacked sideloaded extensions. You will no longer be able to load an extension via the Windows registry by creating an entry with an extension’s directory (i.e. unpacked) after Firefox 61. Starting with Firefox 62, extensions sideloaded via the Windows registry must be complete XPI files (i.e. packed).

Support for unpacked extensions was originally a feature used by legacy extensions. With the release of Firefox Quantum (57) and the transition to the WebExtensions architecture for add-ons, support for unpacked extensions is no longer required. Maintaining support for both unpacked and packed extensions places a significant technical burden on the engineering and testing organizations, and removal of the legacy unpacked extension code helps Mozilla preserve the long-term stability of Firefox.

If you are the developer of an extension that has been installed via the Windows registry as an unpacked directory, your extension will continue to work through Firefox 61. Starting with Firefox 62, however, your extension will be no longer be loaded by Firefox. To avoid this situation and ensure users do not lose functionality, please pack your extension and update the Windows registry entry to use the packed XPI file (see MDN for detailed instructions).

Note: this does not impact the use of unpacked extensions for development. Temporarily loading and debugging an extension either via the about:debugging page or via the web-ext tool will continue to be supported; both methods will still be able to load extensions contained within a filesystem directory. Developers will not be required to sign or pack their extensions into an XPI file for development purposes.

Please do not hesitate to contact me if you have any questions or concerns.

Mike Conca
Product Manager, Firefox WebExtensions


(erosman) #2

I have been developing on unpacked extensions from the start by creating a text file in Firefox /extensions folder with extension ID that points to the location on filesystem.

The Temporarily loading has never been an options since that requires loading repeatedly and every time Firefox starts, in addition to loss of user data on uninstall (on shut down).

Extensions often require road-testing and continuous testing/monitoring which is not practical with Temporarily loading, even though development has become cumbersome due to the changes in FF55 which resulted in caching extension code Bug 1356826)

I am unclear if the option remains after FF62 or not.


(Mike Conca) #3

This path is similar to about:debugging and doesn’t verify signatures. It should continue to work after Firefox release 62.

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