The repo appears to be working for installing/updating packages. Mozilla should allow file listing which should fix the 404s, and make this repo behave as expected when manually browsed (Apparently hosted on a Google webserver; maybe Google forbids this?).
apt-get changelog firefox
Get:1 store: firefox 138.0.3~build1 Changelog
Fetched 129 B in 0s (0 B/s)
firefox (138.0.3~build1) UNRELEASED; urgency=medium
* N/A
-- Mozilla <release@mozilla.com> Mon, 12 May 2025 12:40:33 -0000
date
Tue May 13 08:56:09 AM PDT 2025
Or, to really prove it to yourself, you can re-download the package:
I will have to look into that more tomorrow. My only Debian desktop is a laptop at family's house and currently asleep. It mentioned an error with the repository but my first troubleshooting step was to try to manually verify I could _get_ to the repo in a browser.