Source please.
Never mind, it's simply wrong so don't even worry about it!
/usr/portage/www-client/firefox-bin/firefox-bin-69.0.ebuild
MOZ_HTTP_URI="https://archive.mozilla.org/pub/mozilla.org/${MOZ_PN}/releases/"
...
SRC_URI="${SRC_URI}
amd64? ( ${MOZ_HTTP_URI%/}/${MOZ_PV}/linux-x86_64/en-US/${MOZ_P}.tar.bz2 -> ${PN}_x86_64-${PV}.tar.bz2 )
x86? ( ${MOZ_HTTP_URI%/}/${MOZ_PV}/linux-i686/en-US/${MOZ_P}.tar.bz2 -> ${PN}_i686-${PV}.tar.bz2 )"Debian and Ubuntu don’t build from sources?
You can notice by looking at the build time in the version string.
This makes it impossible to share a profile between two GNU/Linux distributions (or even the official binary and the distribution binary) without hacking with the current versions, even if they are effectively the same version: one will complain that the profile has been run with a more recent version.
(But I sure expect and want my distributions to rebuild Firefox - I trust Debian for making sure no bit of proprietary code is here, and makes tracking opt-in, more than Mozilla)
And to save you a click, they compile it from a source tarball.
[1] https://git.archlinux.org/svntogit/packages.git/tree/trunk/P...
https://git.archlinux.org/svntogit/packages.git/tree/trunk/P...
http://ftp.mozilla.org/pub/firefox/releases/69.0/
All of the various Linux distributions just repackage those binaries. iOS and Android are distributed only through the App Store and Google Play.
The BSDs and other ("tier 3") platforms have to compile from source and distribute their own packages:
https://developer.mozilla.org/en-US/docs/Mozilla/Supported_b...