$ git clone -n https://src.fedoraproject.org/rpms/xtensor.git /var/lib/mock/f45-build-39146-732/root/chroot_tmpdir/scmroot/xtensor
Cloning into '/var/lib/mock/f45-build-39146-732/root/chroot_tmpdir/scmroot/xtensor'...
$ git fetch origin de2bc5c4a12b8d30771886e3cbd7154cc2ad8799:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xtensor
 * [new ref]         de2bc5c4a12b8d30771886e3cbd7154cc2ad8799 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at de2bc5c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild