$ git clone -n https://src.fedoraproject.org/rpms/rust-dummy.git /var/lib/mock/f45-build-41381-782/root/chroot_tmpdir/scmroot/rust-dummy
Cloning into '/var/lib/mock/f45-build-41381-782/root/chroot_tmpdir/scmroot/rust-dummy'...
$ git fetch origin faed287ca77443576e110c907b70aed8f110d347:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-dummy
 * [new ref]         faed287ca77443576e110c907b70aed8f110d347 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at faed287 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild