Re:Firefox Hardware Report for Web Developers
by Manishearth on Thursday December 15, 2016 @02:21PM
(#13187341)
Even if you don't trust Mozilla, the list of things Firefox collects as telemetry on release is extremely limited. (You will have to trust that the binary you downloaded is built from source though, but you can build yourself and/or turn the pref off of you care that much).
(I more or less instinctively opt out of data collection and have never enabled it in Firefox.)
Still, the self selection bias is a curiosity.