$ git clone -n https://github.com/xcp-ng-rpms/libtdb.git /var/lib/mock/v8.3-incoming-10948-29394/root/chroot_tmpdir/scmroot/libtdb
Cloning into '/var/lib/mock/v8.3-incoming-10948-29394/root/chroot_tmpdir/scmroot/libtdb'...
$ git fetch origin 1cccd97882e76227a65208a77e563d0ebf1f4a26:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libtdb
 * [new ref]         1cccd97882e76227a65208a77e563d0ebf1f4a26 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1cccd97 Import libtdb-1.4.14-1.xs8.src.rpm