It only returns a subset of user data https://github.com/NodeBB/NodeBB/blob/master/src/posts/user.js#L24-L28
If you want to add more you can do so in a plugin, using the hook filter:posts.modifyUserInfo
Is it possible to 'hide' a category for people who are below 18 years? This for adult content what for kids isn't allowed to see.
@MJ you can create a new group for people "over 18" and then create a new category for "18+ content" and give the permission for access, read, write, etc only to people in that group.
@PitaJ I know but is there a way that people over 18 years automatically given access in the group or something like that?