$ git clone -n https://github.com/xcp-ng-rpms/dev86.git /var/lib/mock/v9.0-incoming-11256-29612/root/chroot_tmpdir/scmroot/dev86
Cloning into '/var/lib/mock/v9.0-incoming-11256-29612/root/chroot_tmpdir/scmroot/dev86'...
$ git fetch origin 45c5acaa3c48eef47938f0049191bdcbe45d611b:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/dev86
 * [new ref]         45c5acaa3c48eef47938f0049191bdcbe45d611b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 45c5aca Upstream sources fetched with fedpkg