XDown од namii

XDown is a simple add-on that will allow you to directly download videos/GIFs from Twitter/X without the use of any third-party APIs or apps. It sends no data externally and it uses Firefox's native Downloads API. It cannot access protected posts or posts that you can't already view.

Animated GIFs are saved as MP4 because that's how Twitter delivers them.

After activating the add-on, it will add a button on the action toolbar of the post next to the share button.