$ git clone -n https://src.fedoraproject.org/rpms/libaribcaption.git /var/lib/mock/f45-build-15841-480/root/chroot_tmpdir/scmroot/libaribcaption
Cloning into '/var/lib/mock/f45-build-15841-480/root/chroot_tmpdir/scmroot/libaribcaption'...
$ git fetch origin 3a00091c4c2d8e8d48ef7d9e071687d018b61202:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libaribcaption
 * [new ref]         3a00091c4c2d8e8d48ef7d9e071687d018b61202 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a00091 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild