The appimageTools attrset contains utilities to prevent
the usage of appimage-run to package AppImages, like done/attempted
in #49370 and #53156.
This has the advantage of allowing for per-package environment changes,
and extracts into the store instead of the users home directory.
The package list was extracted into appimageTools to prevent
duplication.
This adds a best-effort hack to run AppImages, which currently don't
work out-of-the-box on NixOS. This is not preferable to using packaged
applications, but may help users if the application they want to run
is not in nixpkgs.
It uses the package list from the Steam chroot, but without Steam
packages.
