Except that scenario is not plausible at all. Why would you be downloading a network installer only to move it with USB to another supposedly "secure" machine

Except that scenario is not plausible at all. Why would you be downloading a network installer only to move it with USB to another supposedly "secure" machine just so THAT machine can then do the downloading part instead of just downloading the binary on that machine in the first place? Secondly who is downloading Firefox binaries off of Mozzilla website for a "secure" machine? That only happens if you are running Windows and at that point your pants are already soiled. Most plausible is that some IT department would have same installer on all the machines and then Mozzilla would know that all these machines belong to same organization, but if your IT department is running network installer for every instance for Firefox they install then please fire your IT department. Literally all this info does is to tell Mozzilla that you installed a Firefox or if you are some kind of weirdo who moves some 10kb web installer from friend to friend to install Firefox they might know that all these people at some level know each other, but again this only applies to Windows users. I just don't understand why HN is making this out to be some Firefox killer.