We already removed it from the online docs with #35132.
Currently it can only be "Built-In Types" (Variant types) or "Core"
(everything else), which is of limited use.
We might also want to consider dropping it from `ClassDB` altogether
in Godot 4.0.
I have added a small code sample to show how to automate the process of port forwarding (and closing after you are done).
Thanks to @mhilbrunner for explaining how to achieve t0his (see #18780)