No. Firefox always randomizes the extension ID used for URLs to web accessible resources on each restart [1]. Apparently, manifest v3 extensions on Chromium can now opt into similar behavior [2].

[1]: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

[2]: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

It doesn't work. The person who posted the comment you're responding to has absolutely no idea what he's talking about. He confabulated the entire explanation based on a single misunderstood block of code that contains the comment «Remove " - Chrome Web Store" suffix if present» in the (local, NodeJS-powered) scraper that the person who's publishing this data themselves used to fetch extension names.

I don't see any evidence of this happening in Firefox. Either it's more difficult or they just didn't bother, either way I'm happy.

Edit: Can't find much documentation on exactly how the anti-fingerprinting works, but this page implies that the browser blocks extension detection: https://support.mozilla.org/en-US/kb/trackers-and-scripts-fi...

An ideal implementation of the same origin policy would make it impossible for a site (through a fetch call or otherwise) to determine whether an extension resource exists/is installed or the site simply lacks permission to access it.

I imagine that it would require browsers to treat web requests from JS differently from those initiated by the user, specifically pretending the JS-originating requests are by logged-out or "incognito" users (by, I suppose, simply not forwarding any local credentials along, but maybe there's more to it than that).

Which would probably wreak havoc with a lot of web apps, at least requiring some kind of same-origin policy. And maybe it messes with OAuth or something. But it does seem at least feasible.

Firefox already mitigates this by randomizing the extension path: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

    The file is then available using a URL like: moz-extension://<extension-UUID>/images/my-image.png"
    <extension-UUID> is not your extension's ID. This ID is randomly generated for every browser instance.
    This prevents websites from fingerprinting a browser by examining the extensions it has installed.

I made the mistake of trying to skim the code hastily before I had to leave to run an errand, and yes it turns out I was wrong, but please refrain from the personal comments, and no, I don't have any such "habit."