Applebot is Apple's in-house web crawler for Siri and Spotlight

Apple confirmed its Applebot web crawler which is an in-house search engine crawler. Applebot is currently used to power services like Siri and Spotlight on iOS and OS X platforms but could very well evolve as a standalone search engine if Apple finds that necessary (i.e. as a default search in its Safari browser). Note that Apple did not renew an agreement with Google for search service and since Apple has been shedding Google services (Maps) for some time now, it may decide to re-enter search even for its own uses.

Apple has historically worked on search engine functionality for the web, Sherlock was a huge feature of OS 9.