GNU IceCat

★★★☆☆

More than Waterfox or LibreWolf, IceCat can be described as “Firefox Minus Firefox,” as its primary purpose is to remove the branding, connections to Mozilla services, and any non-Free-with-a-capital-F add-ons.

At present, IceCat is based on an older Firefox ESR release (115) than Waterfox (128), but it does appear to still be maintained.

Syncless and Add-Ons

Like Ungoogled Chromium, all the sync and Mozilla website/service connections have been removed, though you can still go to the Firefox add-ons site yourself or install add-ons manually. There’s also a GNU-curated collection of add-ons, but it doesn’t seem to have been updated since mid-2023 (and the link from the application settings is broken), so you’re better off using the GNU site to vet license compatibility, then go to the Firefox site to get the current version of the add-on.

KeePassXC-Browser is on their list, though I would’ve tried it anyway – and I was able to connect the native Fedora package of IceCat using the “Firefox” settings on KeePassXC.

JavaScript License Checks

IceCat also adds GNU LibreJS, an add-on that blocks JavaScript that isn’t known to be or labeled as GPL-compatibly licensed (unless it’s really small). That’s an interesting ideological take, but the free your JavaScript spec hasn’t made a dent in the growing web application landscape in the decade it’s been online. I had to whitelist my entire Nextcloud server on LibreJS to get it to function, and Nextcloud is AGPL3 licensed!

Availability

GNU doesn’t distribute installers themselves, just scripts to build it from Firefox’s source code. Fedora packages a version of it with some additional add-ons that do things like add alternatives to some of the specific scripts that are blocked by LibreJS.

Overkill

I would only recommend IceCat if you’re really serious about using only free-as-in-libre software. (And in that case, I assume you’re not running on Windows or macOS in the first place.) Even then, I’d suggest LibreWolf, which has similar goals but is more up to date capability-wise and appears to be better maintained. And if you really want to block non-Free JavaScript, well, you can always install LibreJS on there.