uBlock Origin WebExtension lands on Firefox AMO

The WebExtension version of the popular content blocker uBlock Origin has landed on Mozilla's official Add-ons website for the Firefox web browser.

A big upcoming shift from legacy add-ons to WebExtensions forces add-on developers to port their legacy add-ons to ensure compatibility with Firefox 57 and newer versions of the browser.

Mozilla plans to cut off legacy support in Firefox 57 Stable which means essentially that add-ons that are not WebExtensions by the time won't work anymore in the web browser.

Legacy add-on developers face three major issues: first that Mozilla is still working on WebExtension APIs, second that WebExtensions will be limited in what developers can do with them when compared to legacy add-ons, and third that it is just a couple of months before the switch happens.

uBlock Origin WebExtension on Firefox AMO

Work on a WebExtension version of uBlock Origin began back in October 2016. The extension was released on GitHub back then which meant that it was not signed at that point in time. Users who were interested in the new version were only able to install it as a temporary add-on. Good for testing, but not really practicable for every day use.

The move to being distributed through Mozilla's official add-on repository takes care of the issue. The WebExtension version of uBlock Origin is available on the development channel on AMO currently.

Firefox users who want to install the extension can do so in the following way:

1. Load the official uBlock Origin page on the Mozilla website.
2. Scroll down on the page until you find the Development Channel section on it.
3. Click on Development Channel to expand it.
4. Either click directly on the "add to Firefox" link to install the latest build -- which is the WebExtension version of uBlock Origin", or click on "see complete development channel history" to list previous versions as well.

Note: Existing uBlock Origin users will notice a delay during the process. This is caused by the importing of data from legacy storage to WebExtension storage. The process may take up to five minutes. The legacy storage won't be touched during the process so that it is possible to return to the legacy extension at a later point in time. The WebExtension storage will be deleted however when you uninstall the uBlock Origin WebExtension.

Other things worth noting are:

• The new version is a hybrid extension right now. It will show up as legacy in about:addons.
• script:contains filter do not work.
• cosmetic filters are limited as the browser's user styles cannot be used for that anymore.
• Users who are on the "legacy" dev channel will notice that the "dev channel will cease to work". These users need to install the new version manually it appears.

Closing Words

The publication of the WebExtension version of uBlock Origin on Mozilla AMO marks the next step in the development of the new version of the popular add-on for Firefox. There is work to be done for sure, but Gorhill still has several months before the change hits Firefox.

The first version is less powerful right now than the current legacy add-on version for Firefox. Most Firefox users may want to stick with the legacy add-on version for now because of that.