$ git clone -n https://src.fedoraproject.org/rpms/plasma-oxygen.git /var/lib/mock/f41-build-1012484-17768/root/chroot_tmpdir/scmroot/plasma-oxygen
Cloning into '/var/lib/mock/f41-build-1012484-17768/root/chroot_tmpdir/scmroot/plasma-oxygen'...
$ git fetch origin dc98389b93c413c62600ef39516ab7cb74ae7531:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-oxygen
 * [new ref]         dc98389b93c413c62600ef39516ab7cb74ae7531 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc98389 6.1.0