[tomrittervg]

I wasn't aware that any distribution (besides Tor Browser) was building Firefox (or anything really) reproducibly.

There's debian's https://reproducible-builds.org/ effort, but I thought that wasn't making much progress lately, nor was it deployed.

Could you provide more info on what distro you're using, or how they're doing this?

[srazzaque]

S/he may be referring to Gentoo Linux.