In the current Cloud-init for VyOS, the DataSourceOVF.py is modified to provide additional attributes: https://github.com/vyos/vyos-cloud-init/blob/d4004ac6ea1c7c03a35d9410f7c70ab423c926bb/cloudinit/sources/DataSourceOVF.py#L418

This is the only one difference, except configuration files, between the upstream Cloud-init and VyOS variant.

If we find out a way to pass additional configuration from OVF in another native way, this allows us to make updates and maintenance of Cloud-init much easier. So we will be able to add new platforms support and other upstream improvements quicker.