$ git clone -n https://github.com/xcp-ng-rpms/libtdb.git /var/lib/mock/v8.3-u-pcoval1-11006-29440/root/chroot_tmpdir/scmroot/libtdb
Cloning into '/var/lib/mock/v8.3-u-pcoval1-11006-29440/root/chroot_tmpdir/scmroot/libtdb'...
$ git fetch origin 279d4e0d4356fdb8178b44c84589b7db42ab085a:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libtdb
 * [new ref]         279d4e0d4356fdb8178b44c84589b7db42ab085a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 279d4e0 bump release for test build