$ git clone -n https://src.fedoraproject.org/rpms/xylib.git /var/lib/mock/f45-build-39170-732/root/chroot_tmpdir/scmroot/xylib
Cloning into '/var/lib/mock/f45-build-39170-732/root/chroot_tmpdir/scmroot/xylib'...
$ git fetch origin be8f39102d014786a74e79604b1e75de77b7c056:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xylib
 * [new ref]         be8f39102d014786a74e79604b1e75de77b7c056 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be8f391 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild