This vector is only applicable when using authentication.  When a user is logged in, every field within the user table is accessible through this vector.  The value returned will be based on which user is currently logged in.  The vector name used in the vector should correspond to the vector name assigned to the field your referencing.

Examples

{{current_user:first_name}}
This will get the value in the field "first_name" for the current logged in user.  If the current user is not logged in then this will return nothing.

{{current_session:first_name|default=John}}
This will do the same thing as the above vector but if no value exists for that field, it will return "John".