[Request]: How to create new fields in default User Content Type through plugin

[maxpropp]

Summary

It would be great to have a documentation that explains how to add new fields to the user content type through plugin.

Also if it explains how to create relations between an existing content type with the plugin's content type would be awesome.

Why is it needed?

The documentation for plugin development is scarce.

Suggested solution(s)

No response

Related issue(s)/PR(s)

No response