Agreed, and it's become common on many more cars than supercars to add valves to make exhausts noisier. I suspect these valves are not triggered in regulatory exhaust noise tests.

From Jaguar's website:

  Every F‑TYPE is fitted with an Active Sports Exhaust 
  that creates a race‑car inspired crescendo. 
  The exhaust system reacts to throttle position, speed 
  and engine revs by opening active valves. When open, 
  these valves allow exhaust gases to take a more direct,
  less restrictive route through the rear silencer
  producing a much richer, more exhilarating sound. Where
  fitted, the Switchable Active Exhaust, allows you to
  manually open the exhaust valves so you can enjoy
  F‑TYPE’s stirring soundtrack at all engine speeds. This 
  feature is optional on F‑TYPE and standard on all other 
  models.