$ git clone -n https://src.fedoraproject.org/rpms/rust-gvdb.git /var/lib/mock/f45-build-42234-791/root/chroot_tmpdir/scmroot/rust-gvdb
Cloning into '/var/lib/mock/f45-build-42234-791/root/chroot_tmpdir/scmroot/rust-gvdb'...
$ git fetch origin b6bcbb5fd19c2f5bff21103486cf53786633561c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gvdb
 * [new ref]         b6bcbb5fd19c2f5bff21103486cf53786633561c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b6bcbb5 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild