One of the badly documented you can say is the facebook api. Its all because the documentation is not up to date and it is really hard for a beginner to start with by reading the documentation.
One such un-updated, missing is graph api is family details. For example details of parents, brothers, sister, aunties etc etc.
To obtain family details you need ‘user_relationship_details’ permission. ‘family’ is one of the connections to ‘user’. So if you are using php, the call will be as follows:
This will provide you with an array of user id of the family relationship holder and the relationship, since i have limited the fields only to ‘id’.
You can call and see by yourself all other details passed via the API.