The @class tag is used to put documentation for objects. There is no sub-tag, but you could (in fact, if you want to do a good documentation of your object, you must) put documentations inside of the object dclaration.

/*!
 * @class       XWing
 * @abstract    One of the best space interceptor.
 * @discussion  The mythic spaceship used by the
 *              Rebellion against the Empire.
*/
class   XWing : public SpaceShip
{
public:
    /*! @var r2d2  Droid for mechanical help */
    mechanicDroid      *r2d2;
    /*!
     * @function   go
     *             Launch the ship to do its mission.
     * @param      urgency    Level of urgency of the mission.
     * @result     Boolean value that indicate the result
     *             status of the mission.
    */
    bool               go(int urgency);
private:
    /* @var mission  The current mission */
    void               *mission;
};