A package is being made as you read or made already (check on obextra)

This is a library that is a weston dependency and for whatever reason arch devs added a systemd dependency that is being totally unused by the package. Not only this, they added the dependency and end their PKGBUILD with this:

  rm -rf "$pkgdir"/{etc,usr/bin,usr/lib/systemd} 

There is no trace of systemd in this library. Their previous pkg was a mess, it was listed as a library and included pipewire executables and configuration files.

Till a package is provided by obarun use this pacman option:

$ sudo pacman -Sdd libpipewire02

The resulting update just removes the executables and configurations from /etc and /usr/bin that shouldn't have been there to begin with.