Never heard of this service. Thanks.

This is a big complaint for me. I know that there is the official standalone APK, but if I am running a de-Googled phone, I want to be able to use Signal and have it update on a regular basis.

I agree. There should have been an official Firefox repo from the beginning.

I do remember twenty years ago, Firefox development was incredibly Windows-centric. At one point it felt as though Firefox for Linux was a second class citizen. This was a radical departure from the Mozilla Suite which was maybe the first major desktop software to go from close to open source. For many years afterward, as a BSD/Linux user, I continued using SeaMonkey for that reason.

I assume having an official repo was just never a priority in the early days.