$ git clone -n https://src.fedoraproject.org/rpms/rust-grep-regex.git /var/lib/mock/f45-build-42215-791/root/chroot_tmpdir/scmroot/rust-grep-regex
Cloning into '/var/lib/mock/f45-build-42215-791/root/chroot_tmpdir/scmroot/rust-grep-regex'...
$ git fetch origin 1e645e01d87a55313ccbc3683ac2564b5e61f28a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-grep-regex
 * [new ref]         1e645e01d87a55313ccbc3683ac2564b5e61f28a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1e645e0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild