$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-9787-28501/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-9787-28501/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 899aadfaeac28d04808ace6d67a161e0d9c6969e:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         899aadfaeac28d04808ace6d67a161e0d9c6969e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 899aadf Import xapi-25.33.1-2.xs8.src.rpm (#114)