$ git clone -n https://github.com/xcp-ng-rpms/libarchive.git /var/lib/mock/v8.3-incoming-9384-28137/root/chroot_tmpdir/scmroot/libarchive
Cloning into '/var/lib/mock/v8.3-incoming-9384-28137/root/chroot_tmpdir/scmroot/libarchive'...
$ git fetch origin ceaa9732cf72cfcd781fdea6e62fde3bd1d032ca:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libarchive
 * [new ref]         ceaa9732cf72cfcd781fdea6e62fde3bd1d032ca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ceaa973 Merge pull request #2 from xcp-ng-rpms/ldconfig