Display panel > Link Display rollout
The Link Display rollout provides controls that alter the display of hierarchical linkages.
Interface
Display Links: Displays a wireframe representation of any hierarchical links affecting the selected object.
Note: Display Links must be turned on in order to see Joint Limits on a inverse kinematics chain.
Link Replaces Object: Replaces the selected object with the wireframe representation of the hierarchical link. This option offers another way to reduce the geometric complexity of selected objects in a scene. See also Display Properties Rollout.
The Draw Links as Lines option in the Viewports panel of the Preference Settings dialog further reduces the display of links to a single line.