$ git clone -n https://src.fedoraproject.org/rpms/libarchive.git /var/lib/mock/f40-build-2241919-53669/root/chroot_tmpdir/scmroot/libarchive
Cloning into '/var/lib/mock/f40-build-2241919-53669/root/chroot_tmpdir/scmroot/libarchive'...
$ git fetch origin af9dc15c7cb98dee85df37a2095cec727ab29f30:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libarchive
 * [new ref]         af9dc15c7cb98dee85df37a2095cec727ab29f30 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at af9dc15 Configure Packit on libarchive package