$ git clone -n https://github.com/xcp-ng-rpms/kernel.git /var/lib/mock/v8.3-u-tae1-10961-29420/root/chroot_tmpdir/scmroot/kernel
Cloning into '/var/lib/mock/v8.3-u-tae1-10961-29420/root/chroot_tmpdir/scmroot/kernel'...
$ git fetch origin 7838d3e9d99d3718e3ddcf05045308cad3dbcb4c:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/kernel
 * [new ref]             7838d3e9d99d3718e3ddcf05045308cad3dbcb4c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7838d3e9d bump release for test build