This is straightness of a linear element on the surface. It looks to be ISO and so could have whatever it is they refer to for orientation of such elements using datum feature references.
3DDave please tell me more. the location of tolerance zone must desine by TED. in this example posiotion of tolerance zone doesn't define. i suggest i shoud be useing TED.
How wide is that tolerance zone? How does it affect the measurement if that origin surface is either not perfectly flat or perfectly perpendicular to the top surface? What mates with the infinitesimally narrow line?
In ISO one can have a datum feature reference for straightness but this application looks like a mess.