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Extensions in Firefox 76

A lot of great work was done in the backend to the WebExtensions API in Firefox 76. There is one helpful feature I’d like to surface in this post. The Firefox Profiler, a tool to help analyze and improve Firefox performance, will now show markers when network requests are suspended by extensions’ blocking webRequest handlers. This can be useful especially to developers of content blocker extensions to ensure that Firefox remains at top speed.

Here’s a screenshot of the Firefox profiler in action:

The Firefox Profiler showing the network section of the marker chart. There is an entry "Extension Suspend" for when the request is blocked by the extensionMany thanks to contributors Ajitesh, Myeongjun Go, Jayati Shrivastava, Andrew Swan and the team at Mozilla for not only working on the visible new features but also maintaining the groundwork that keeps extensions running.

6 comments on “Extensions in Firefox 76”

  1. gwarser wrote on

    How we will know how much is contributed by extension and how much by IPC delays?

  2. Stefan wrote on

    Why does Firefox 75 reset all my settings i do for the addons ? Why does Firefox 75 at every start nag me about the addons have been successfully installed ? They are set in about:config to NOT autoupdate they seem still to do it anyway ! I utterly hate Firefox Quantum !!!!!!!

  3. Alex wrote on

    Man,the 76 version break my favorite addon, “Flash and video download”,and I can’t back to previously version.

    Why you guys change such things so much?And don’t let addons to test with it?

    Please don’t do this,let my addon back.

  4. thesun wrote on

    I wanted to test the update of my extension (xpi) with FF76 not hosted on AMO.
    I followed the link ( But my extension does not update and its version does not change.
    To debug, In the browser console, I can see the call to my https // / updates.json with ok status but the corresponding xpi extension is not installed in firefox.
    An idea ?

    1. Caitlin Neiman wrote on

      Could you re-post this on our community forum ( or ask it in the Add-ons Matrix room ( We have a hard time providing developer support in blog comments. 😉

  5. sunshine wrote on

    Hello Firefox Devs,

    Firefox user here for 10+ years.. Im pretty upset about your constant changes. Old password exporters doesnt work anymore, bookmarks are disappearing, clean and properly working plugins inactivated and removed.. Seriously you want me to type 1000 of login info manually? 🙁 Why are you enforcing your cloud syncing? Tons of very cool addons doesnt work properly with new upgrades..

    My customized firefox losing its previous settings after a refreshing. I dont want to believe in 2020 you need to implement things like this. Instead of constantly changing everything, I think you need to be reliable, otherwise you are using a lot of users.. (as you can see from the yearly stats as well)

    Look at Mac OSx and Safari. They are innovative, but still the same, and dont change standards this often. Please be reliable and dont change things without thinking about compatibility. I dont want to change to Safari, IE, Chrome. Firefox is my home. Please don’t enforce me to change my browser.

    a sad firefox user.