Select an incorrect description for the line type.

The description of a break line correctly indicates that it is used to show where a part of an object has been "broken" away to reveal internal features or to indicate that a certain section is omitted from the drawing for clarity or space-saving. Therefore, it does not describe the internal features themselves; rather, it is more about the external view, suggesting that some parts are not shown in their entirety.

In contrast, the other options correctly reflect the line types involved. An objection line indeed defines the shape of an object, helping to communicate its outline. A hidden line effectively illustrates features that are not visible from the current viewpoint, such as internal details or parts obscured by other components. Lastly, a leader line serves the specific purpose of calling out details or labeling features on the drawing, providing clarity and context to the viewer regarding what elements require attention. This makes the other descriptions accurate representations of their respective line types.