Elasticsearch and Alfresco have two different data models, where the same concept (i.e. field) is sometimes captured in a different way.
We should implement (or integrate an existing) service for managing the translation between one side and the other, and in general for interacting with those data models (e.g. checking if a field is a property or a field like SITE)
The ticket has been raised during the faceting tickets, where we need to understand from a REST API request, how the requested fields must be mapped to Elasticsearch. I've inserted a static Set in FieldMappingHelper in order to understand if a field belongs to the basic fields indexed regardless the content model, but we need an organic design about a service that is able to cohesively manage this concept.