People new to Nix/NixOS always seem to think that flakes are some kind of fundamental shift or something and if you don’t use flakes, you’re not going to be ready for the future or whatever.
No, they’re not. They’re “just” a standardised method of composing separate Nix projects.
In the most common NixOS case (and especially when starting out) you have exactly one external Nix project you depend on and that’s Nixpkgs. Flakes provide very little (if any) benefit in this specific case.
If you’re starting out, you don’t need to care one bit about flakes, experimental features and the documentation of features that are not intended to be commonly used yet (especially not for beginners).
The way it’s written doesn’t say whether it simply isn’t made to work for Firefox or whether it couldn’t be made to work for Firefox. Fortunately, the latter appears to be the case.
Detecting extensions using web accessible resources is not possible on Firefox as Firefox extension ID’s are unique for every browser instance. Therefore the URL of the extension resources cannot be known by third parties.
and also for Chrome:
in manifest v3 extensions will be able to enable ‘use_dynamic_url’ option, which will change the resource URL for each session (browser restart). This will render this detection method unusable.
Though it should be noted that this method isn’t the only way to detect extensions.
I use NixOS but I don’t bother with automatic deployment or even automatic formatting. I don’t feel it’s necessary in a homelab setting as hardware failure rarely happens at such small scale and the manual steps left aren’t that significant.
This kind of integration testing is best left up to the individual distros. Same as the integration (as in: packaging) itself.
Distros don’t want your binary package, they want your source code, build instructions and a build system that won’t make them cry. Some distros even explicitly disallow re-packaging external binary distributions.
As a distro maintainer, I appreciate your wish to do QA on all the distros but that’s just too much work. You focus on making your software better, we focus on making it work with the rest of the software ecosystem.
Providing a package for one or two distros (i.e. your favourite one) is good practice to ensure your software can be reasonably packaged but it’s not the primary way your users should receive your package in the traditional Linux distro model.
Additionally, you might want to package your software for one of the cross-distro package managers such as Flatpak, AppImage, Snap, Nix, Guix, distri or homebrew. This can serve distro maintainers as a point of reference; showing how it is intended to work so they can compare their packaging effort. If there’s some bug present in the distro package but not the cross-distro package, that’s a good sign the issue lies in the distro packaging for example.
Again, don’t put much time in this. Focus on your app.