Service specialized in detecting and analyzing human faces: location, attributes (approximate age, emotion), and face comparison/verification. 1:N facial identification is subject to limited-access restrictions under Microsoft's responsible AI policies.
In AI-901 it's tested on the difference between face detection (finding that a face is present, generally allowed) and facial identification (recognizing whose face it is, restricted under Responsible AI). Part of the broader Computer Vision service.
Azure AI Face is a concept that can show up on the exam. Check the full guide to see it in context.