I will break these points down into subtasks soon.
(This is the output of our task breakdown)

• Extract the wbgetentities call for all needed properties(entities) during rendering into another service
  • So the "magic" prefetching via the label / term lookup would already prefetch the details for the needed entities (this behaviour should be researched and documented later)
  • The service would always fetch all of the information that we need (labels, descriptions and aliases in all possible languages & existence of the entity)
  • This service would cache responses in the process
  • This service would allow retrieval of parts of the result?

• Use the new wbgetentitie service in the ApiPrefetchingPropertyTermLookup (implemented in a previous sprint)

• Create a service that is an EntityExistanceChecker with method ->isDeleted()
  • One implementation would use an EntityTitleLookup and the $title->isKnown() method
  • Another implementation would use the new wbgetentities service

• Alter EntityUrlLookup interface to have 2 methods, the getFullUrl (for use in contexts like search), and a new one getUrl which gives the localUrl for local entities and the full url for remote entities. (also document this in the phpdc well)

• Rewrite LabelsProviderEntityIdHtmlLinkFormatter to remove use of the EntityTitleLookup service, and instead use the new EntityExistanceChecker service, and our already created EntityUrlLookup and EntityTitleTextLookup

• Rewire the federated properties entity type service definition for the EntityIdLabelFormatter to use LabelsProviderEntityIdHtmlLinkFormatter (and delete the temporary other formatter?)

• Find and document this prefetching magic that happens when rendering an entity page (either for the whole entity or just terms / labels)

sub tasks created and task breakdown done:

• T251237: Extract the wbgetentities call for all needed properties(entities) during rendering into another service
• T251238: Use the new wbgetentities service in existing classes
• T251239: Create a service that is an EntityExistenceChecker
• T251241: Alter EntityUrlLookup interface to allow for context relevant URL
• T251242: Rewrite LabelsProviderEntityIdHtmlLinkFormatter to remove use of the EntityTitleLookup service
• T251243: Rewire the federated properties entity type service definition for the EntityIdLabelFormatter
• T251244: Find and document the prefetching logic that happens on page render

This can now be verified here: https://wikidata-federated-properties.wmflabs.org/wiki/Item:Q8