Goes further than mere overtures (6)
I believe the answer is:
passes
'goes' is the definition.
(passing is a kind of going)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for passes that I've seen before include "Advances" , "never fails to get?" , "Moves like mountain gaps" , "Dies, euphemistically" , "Routes through mountains" .)