$ git clone -n https://github.com/xcp-ng-rpms/xen.git /var/lib/mock/v8.2-u-tescande1-8889-27843/root/chroot_tmpdir/scmroot/xen
Cloning into '/var/lib/mock/v8.2-u-tescande1-8889-27843/root/chroot_tmpdir/scmroot/xen'...
$ git fetch origin 1ccd86afa0a0e7f9a5685640a469f5294610d261:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xen
 * [new ref]         1ccd86afa0a0e7f9a5685640a469f5294610d261 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1ccd86a bump release for test build