$ git clone -n https://github.com/xcp-ng-rpms/xapi /var/lib/mock/v8.3-incoming-10781-29291/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-10781-29291/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 2bec0e284c3bdb1d9be96a709fdc96e19c64b721:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         2bec0e284c3bdb1d9be96a709fdc96e19c64b721 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2bec0e2 xapi.spec: don't treat all plugins as a single argument (#120)