The changes for the GTK 4 theme seem to be backwards compatible, and
small enough to not require version specific theming (at least at
4.6). Based on comments from developers, this shouldn't change in the
future either. Drop the versioning support, and only ship single
theme, to simplify both maintenance and building.
Intended to help users who want to add Arc styling to GDM by
replacing the default gnome-shell-theme.gresource. Compiled
gresources are simply installed alongside the shell themes, and
it is up to users to make any use of them.
The openbox theme was included from the arc-design repo under the
impression that it was specifically created for that project.
However, it was actually copied from an existing project [1].
It doesn't make sense to have the theme developed in two separate
locations. The themes supported in this repo should be limited to
GTK and GTK-based desktops, as it was with the original Arc-theme
project.
The Arc openbox theme remains available from its original repository.
[1] https://github.com/dglava/arc-openbox
optipng is not required for building the theme, but only used to
optimize the rendered PNG assets, which will reduce the size of the
built theme marginally. Make it optional, and only used if available
on the build environment, to avoid dependency hell with some
distributions, e.g. Clear Linux [1].
[1] https://github.com/jnsh/arc-theme/issues/52#issuecomment-642966596