$ git clone -n https://src.fedoraproject.org/rpms/powwow.git /var/lib/mock/f45-build-28863-633/root/chroot_tmpdir/scmroot/powwow
Cloning into '/var/lib/mock/f45-build-28863-633/root/chroot_tmpdir/scmroot/powwow'...
$ git fetch origin 3fc215cbf12d4e6081fccf6e7015feb787600209:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/powwow
 * [new ref]         3fc215cbf12d4e6081fccf6e7015feb787600209 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3fc215c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild