The `pkgs.yabar` package is relatively old (2016-04) and contains
several issues fixed on master. `yabar-unstable` containsa recent master
build with several fixes and a lot of new features (I use
`yabar-unstable` for some time now and had no issues with it).
In the upstream bugtracker some bugs could be fixed on ArchLinux by
simply installing `yabar-git` (an AUR package which builds a recent
master).
To stabilize the module, the option `programs.yabar.package` now
defaults to `pkgs.yabar-unstable` and yields a warning with several
linked issues that are known on `pkgs.yabar`.
The test has been refactored as well to ensure that `yabar` actually
starts (and avoid non-deterministic random success) and takes a
screenshot of a very minimalistic configuration on IceWM.
Fixes#46899
8b58a7187c