Comment 3 for bug 1913388

Typically a source package (.dsc) publishes all binary packages (.deb) for all architectures into the same component. That is the default behavior of launchpad. We try to avoid split-publishing of .deb into main/universe where possible, or split-publishing across different architectures. Especially since some otherwise graphical/desktop stack packages at times end up in the reverse build-dependencies cycles to build otherwise CLI-only software. The obvious example being cmake.

s390x is explicitly an Ubuntu Server architecture only. Thus whilst many desktop packages are built automatically on s390x they are provided on the best effort basis out of convenience. It would require manual interventions and changes to exclude them on s390x.

Similar caveats apply on other architectures too. At the moment we only fully support Ubuntu Desktop on amd64; Pi 4+ arm64.