$ git clone -n https://src.fedoraproject.org/rpms/mbedtls.git /var/lib/mock/f45-build-18155-510/root/chroot_tmpdir/scmroot/mbedtls
Cloning into '/var/lib/mock/f45-build-18155-510/root/chroot_tmpdir/scmroot/mbedtls'...
$ git fetch origin a3a133eafbb023814a59e7b2609fea9968a6aa4e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mbedtls
 * [new ref]         a3a133eafbb023814a59e7b2609fea9968a6aa4e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a3a133e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild