GQL is an HTTP endpoint. The question is, how are you schematizing, documenting, validating, code-generating, monitoring, etc. the request and response on your HTTP endpoints? (OpenAPI is another good choice.)

Really? Hmm... where in the HTTP spec does it allow for returning an arbitrary subset of any specific request, rather than the whole thing? And where does it ensure all the results are keyed by id so that you can actually build and update a sensible cache around all of it rather than the mess that totally free-form HTTP responses lead to? Oh weird HTTP doesn't have any of that stuff? Maybe we should make a new spec, something which does allow for these patterns and behaviors? And it might be confusing if we use the exact same name as HTTP, since the usage patterns are different and it enables new abilities. If only we could think of such a name...