MarsSeed [1] filed a deletion request for openmodelica-omshell [2]: Cleanup of defunct/EOL OpenModelica component package. Its repo is archived since 2019.
Upstream had transitioned the separate module codebases into a common OpenModelica monorepo. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/openmodelica-omshell/
