Explanation:

Box 1: LargeFaceListID
LargeFaceList: Add a face to a specified large face list, up to 1,000,000 faces.
Note: Given query face's faceId, to search the similar-looking faces from a faceId array, a face list or a large face list. A "faceListId" is created by FaceList - Create containing persistedFaceIds that will not expire. And a
"largeFaceListId" is created by LargeFaceList - Create containing persistedFaceIds that will also not expire.
Reference:
https://docs.microsoft.com/en-us/rest/api/faceapi/face/findsimilar