$ git clone -n https://github.com/xcp-ng-rpms/samba.git /var/lib/mock/v8.3-u-pcoval2-10606-29161/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10606-29161/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin 637a43ae07b20a565e117669e2efbf5480bf39fd:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/samba
 * [new ref]         637a43ae07b20a565e117669e2efbf5480bf39fd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 637a43a bump release for test build