Works fine. Also the only Reverse search extension that actually is able to search images from https://addons.mozilla.org Other ones somehow refuse to do that...
It's because they inject a content-script instead of "listening" when an image is right-clicked. For security reasons, this is not allowed on addons.mozilla.org.
Works well! The icon in the context menu makes it easier to find this function quickly. Unlike the original Add-on by Google, this also works with Multiprocess enabled. Terrific!