(This item pertains to the check boxes on the General tab of the Setup Options dialog box. You can open it through the F5 key or through the Edit | Preferences | Setup menu option.)
Selecting this option toggles between the legacy version of Profile 2D (selected) and the latest version of Profile 2D (de-selected).
The legacy Profile 2D has the options of Matching Edge and Under Scan which are no longer available in the latest version of Profile 2D.
For more information on using the Legacy Profile 2D functionality, see the vision topic "Vision Profile 2D".