Do not overfly final
 

I was listening to the online scanner for AUS at liveatc.net and I heard Approach tell an aircraft to not overfly the final. Does that mean the FAF or the approach course?

Approach course. It's exactly like if you delay your base-to-final turn too long.

I see. Thank you

They were told this because the controller likely had traffic on the other side of the final approach course, or the extended centerline of the runway. This is common on parallel runways where they don't want one aircraft overshooting his turn to final creating a traffic conflict to the other aircraft on the parallel runway.