$ git clone -n https://src.fedoraproject.org/rpms/plasma-thunderbolt.git /var/lib/mock/f42-build-side-1-3583499-46889/root/chroot_tmpdir/scmroot/plasma-thunderbolt
Cloning into '/var/lib/mock/f42-build-side-1-3583499-46889/root/chroot_tmpdir/scmroot/plasma-thunderbolt'...
$ git fetch origin 2adbb7a54db6711cae7fb452a860266359a6a5a8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-thunderbolt
 * [new ref]         2adbb7a54db6711cae7fb452a860266359a6a5a8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2adbb7a 6.4.2