$ git clone -n https://src.fedoraproject.org/rpms/kf6-purpose.git /var/lib/mock/f42-build-side-1-3573613-46768/root/chroot_tmpdir/scmroot/kf6-purpose
Cloning into '/var/lib/mock/f42-build-side-1-3573613-46768/root/chroot_tmpdir/scmroot/kf6-purpose'...
$ git fetch origin 6d1d40ee126996119dcf2324297743d150c18b3b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-purpose
 * [new ref]         6d1d40ee126996119dcf2324297743d150c18b3b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6d1d40e 6.15 and plasma 3.4 compatibility rebuild