$ git clone -n https://src.fedoraproject.org/rpms/rust-slab.git /var/lib/mock/f45-build-45006-820/root/chroot_tmpdir/scmroot/rust-slab
Cloning into '/var/lib/mock/f45-build-45006-820/root/chroot_tmpdir/scmroot/rust-slab'...
$ git fetch origin 572e5d0db864455fa912f2a3ada40be897a18990:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-slab
 * [new ref]         572e5d0db864455fa912f2a3ada40be897a18990 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 572e5d0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild