How can I remove languages from the /types page and make them inaccessible from /types/language

I want to remove the ability to get auto generated DTOs for Java, Kotlin, and Swift. How can I remove them from the /types page and also inaccessible via /types/language

You can’t remove individual languages, just the entire NativeTypesFeature with:

Plugins.RemoveAll(x => x is NativeTypesFeature);

Otherwise you’d need to add a GlobalRequestFilter which checks the IRequest.PathInfo for invalid requests and return either a 404 NotFound or 403 Forbidden HTTP Response.