$ git clone -n https://github.com/xcp-ng-rpms/branding-xcp-ng /var/lib/mock/v9.0-incoming-10984-29373/root/chroot_tmpdir/scmroot/branding-xcp-ng
Cloning into '/var/lib/mock/v9.0-incoming-10984-29373/root/chroot_tmpdir/scmroot/branding-xcp-ng'...
$ git fetch origin 8c1a863c422f6153c9e1860565795eb34e2acd32:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/branding-xcp-ng
 * [new ref]         8c1a863c422f6153c9e1860565795eb34e2acd32 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8c1a863 New release 8.99.0