There's a lot of changes in the way we're defining new API subsets. The json_rpc API will continue to be supported for existing API subsets, but new API subsets are all defined to be accessible via REST calls.

So instead of using get_methods to discover them, they will be discoverable via an OpenApi json file and/or a swagger user interface. Theoretically an API node operator could expose this json file now, but we haven't documented the best practice for doing so. We're working on that now and it will probably be released as part of the upcoming 1.27.5 release.