Why no header in the msg ?

[YHuniv15]

Hi,

Is it normal tha Postion.msg got only :
float32 x_trans float32 y_trans float32 z_trans float32 x_rot #first element of the quaternion float32 y_rot #second element of the quaternion float32 z_rot #third element of the quaternion float32 w #forth element of the quaternion string segment_name #name of a specific component of the object string subject_name #name of the entire object int32 frame_number #unit of time for each capture string translation_type #Local or Global and no header used ? (stamp +frame_id )

Thanks for help ?