Mozilla announced this week that the organization’s Firefox web browser will stop supporting extension sideloading in Firefox 74.
Current versions of the Firefox web browser support three different methods when it comes to the installation of extensions:
- Install via Mozilla’s official add-ons repository Mozilla AMO.
- Use Firefox’s “Install add-on from file” functionality in the Add-ons Manager. To use it, load about:addons in the Firefox address bar and select Menu > Install Add-on from File. Select the Firefox extension using the file browser that opens to start the installation dialog.
- Place extension files into standard extension folders.
The change removes the third option but does not touch the other two options. The third method caused issues frequently for Firefox users according to Mozilla as these extensions were not installed directly by users of the browser and could not be removed from the add-ons manager either.
While sideloading has been used by legitimate developers to test Firefox installations and organizations to deploy extensions on systems, it has also been abused in the past, e.g. to install malicious extensions in Firefox.
Mozilla plans to remove support in Firefox 74. Here is the full timeline (see our release schedule for Firefox for additional information):
- Firefox 73 (out February 11, 2020) — Sideloaded extensions will be copied to the user’s profile and installed as regular add-ons.
- Firefox 74 (out March 10, 2020) — Sideloading is no longer supported
The change in Firefox 73 ensures that installed extensions won’t be removed without recourse. Firefox users find these extensions in the built-in extension manager from where they may be removed just like any other extension installed in the web browser. Firefox users may remove these extensions then from the web browser in case they have no intention of using them.
Firefox users will benefit from the change as it removes an option that has been abused by malicious actors and also some software companies in the past to install extensions in Firefox.
Firefox users and developers will still be able to install extensions in the browser that are stored locally.
Now You: Do you use extensions that you installed locally in Firefox?