$ git clone -n https://src.fedoraproject.org/rpms/libxkbcommon.git /var/lib/mock/f42-build-3426613-45197/root/chroot_tmpdir/scmroot/libxkbcommon
Cloning into '/var/lib/mock/f42-build-3426613-45197/root/chroot_tmpdir/scmroot/libxkbcommon'...
$ git fetch origin b81c79706f452389d6c99603f07e00c1d0013aca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxkbcommon
 * [new ref]         b81c79706f452389d6c99603f07e00c1d0013aca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b81c797 libxkbcommon 1.8.1