Few related things I had to track down about this site recently:
1. This is an official Mozilla site.
2. Source is at https://github.com/mozilla/releases_insights, under MPL-2.0
3. Thanks to Pascal Chevrel for creating and maintaining this. https://whattrainisitnow.com/humans.txt
As far as I can tell, this is the only official page that documents Firefox 115 ESR being extended for Windows 7-8.1 and macOS 10.12-10.14 up to March 2025.