$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release /var/lib/mock/v8.3-incoming-9667-28393/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-incoming-9667-28393/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin b0edf886c73a3ad7df3a3967b2a26d1ae37496c6:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         b0edf886c73a3ad7df3a3967b2a26d1ae37496c6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b0edf88 Remove noise from patches using git-format-patch options