The contributing page keeps track of how to get involved with the project.
This project is an extension of Gateway API, and may eventually be merged into the main Gateway API repo. As we're starting, this project represents a close collaboration between WG-Serving, SIG-Network, and the Gateway API subproject. These groups are all well represented within the ownership of this project, and the separate repo enables this group to iterate more quickly as this project is getting started. As the project stabilizes, we'll revisit if it should become part of the main Gateway API project.
No. Although this project will provide a default/reference implementation of an extension, each individual Gateway controller can support this pattern. The scope of this project is to define the API extension model, a reference extension, conformance tests, and overall documentation.
Maybe. We're trying to keep the scope of the reference extension fairly narrow and instead hoping to see an ecosystem of compatible extensions developed in this space. Unless a use case fits neatly into the existing scope of our reference extension, it would likely be better to develop a separate extension focused on your use case.