$ git clone -n https://github.com/xcp-ng-rpms/samba.git /var/lib/mock/v8.3-u-pcoval1-11355-29667/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-u-pcoval1-11355-29667/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin 7767c3ad45fea2ba0d426ff9cfca259d31e00aa7:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         7767c3ad45fea2ba0d426ff9cfca259d31e00aa7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7767c3a bump release for test build