Documentation can be found following the link below:
https://api.stackexchange.com/docs/favorites-on-users
public override IBridgeResponseCollection<Question> GetUsersQuestionFavorites(long[] ids, QuestionFavoritesQuery parameters = null) { return GetApiResultCollection<Question, QuestionFavoritesQuery>(ApiMethodEnum.FavoritesOnUsers, CreateIdsVector(ids), parameters); }