You mentioned getfirefox.com and while that was and is the official site, I remember a time (maybe?) when that was registered to a third-party fan of Firefox to promote it who handed it over to Mozilla. That said… I cannot find any evidence to back up this claim after a small bit of Google searching, so I might be wrong. I definitely remember a time after the rebranding was announced but before the full 1.0 launch where the moz website didn’t have an easy or obvious landing page for Firefox because so much website energy was still reserved for the open sourced Mozilla communications suite ;-) It always felt a bit new and edgy to recommend Firefox (Phoenix? Firebird?) back in the old days. Weirdly, there was a time when it was new and edgy to recommend Chrome too. Now it’s probably new and edgy to recommend… ad-blocking? Edge Read Aloud? It was easier when IE provided a common enemy and when Chrome wasn’t the only choice for low performance Android devices, or Safari on iOS.

Re third party sites, it’s likely getfirefox was actually always Mozilla’s (they would have known about the name first, of course) so maybe I’m thinking of “getfirebird.com” or something else like that. It’s even possible that I just assumed it was third-party because it redirected to the main Mozilla site for the longest time. And it really probably doesn’t matter anyway, just a digression. :)