GPU Passthrough with FreeBSD/XEN port, status?

Hello,

Hello, This page ( https://wiki.xenproject.org/wiki/FreeBSD_Dom0 ) has
been around for almost ten years and it contains the following phrase:

Shortcomings:
// among others limitation //
- Missing PCI Passthrough support (Xen/FreeBSD).

What are these limitations related to? As far as I know, Xen is a type
1 hypervisor and it seems that it should not depend very much on the
Dom0 system, which is only a controller/manager.

What is the relationship between FreeBSD XEN port and Citrix? It is an
*unofficial* port and therefore the chances of using GPU Passthrough
with FreeBSD dom0 in the near future are minimal? GPU Passthrough (and
PCI devices in general) is a very popular thing in virtualization.
It's very hard to say that Xen supports FreeBSD/Dom0, and at the same
time basic things are missing for ten years ;-) Thanks!