On: Each Firefox download has a unique identifier

[charcircuit]

It's possible that they are tracking how many times an installer gets used without violating your privacy. Installers can be shared online or you can install it on someone else's computer. It's not like they are specific to a person.

[_abox → charcircuit]

True but why? There just be a really heavy reason to introduce something like this. I don't see it.