Why is the "query" end point not actually listed in the data model?

The "Core" data model lists the endpoints for query definition, query parameter definition, and query service (https://testapi.imis.com/swagger/?url=https://testapi.imis.com/swagger/Enterprise/20.3.149/core.json). It does not, however, actually explain how to call an existing IQA. That information, as far as I can tell, is only available in the article on migrating from the IQA to Query service endpoint (https://developer.imis.com/docs/migrating-from-iqa-to-query-service-endpoint).

I find this odd. Calling an IQA is the most efficient way to get Party data from iMIS if you need to filter for several properties. Why is /query not listed in the authoritative Core data model and tucked away in a tutorial? Is this some blindingly obvious convention of REST APIs I'm missing?