skopeo is a command line utility for various operations on container images and
image repositories. skopeo is able to inspect a repository on a Docker registry
and fetch images layers. skopeo can copy container images between various
storage mechanisms.

umoci modifies Open Container images.

umoci (pronounced /uːmoˈʨi/ or approximately "oo-mo-tchee") is a reference implementation of the OCI image specification and provides users with the ability to create, manipulate, and otherwise interact with container images. It is designed to be as small and unopinonated as possible, so as to act as a foundation for larger systems to be built on top of.

As of 20230831, building .appx images for:

* openSUSE Leap 15.4 (disabled 20240821, smb)
* openSUSE Leap 15.5 (disabled 20250702, smb)
* openSUSE Leap 15.6 (disabled 20260805, smb)
* openSUSE Leap 16.0 (not building `.appx` here)
* openSUSE Tumbleweed

### !!! ATTENTION !!!

As of v2.4.4 of WSL (~ November 19th, 2024), compressed tarballs (as `.wsl` files) are the preferred file format for WSL Distros; Microsoft calls these ModernDistributions and `.appx` can be chosen via a `--legacy` flag.

There are no plans to continue to develop `.appx` Distro releases as they're phased out of the Microsoft Store.