Copper Brake Lines?

[Quarrycars]

When I was building kit cars and doing MOT repairs about 40 Years ago copper tubing could not be used on cars because to concern about cracking due to 'work hardening' caused by vibration.  I have always made brake, fuel and Hydrolastic lines out of cupronickel 'Kunifer' tubing.
I believe the Moscovich (anybody remember those things!) was even recalled to replace the copper lines.
I am surprised to find that copper is now being used, and I assume approved, for brake lines .
What changed?

[peterw]

No idea !!!!  Unless the copper is a composite nowadays

http://www.fedhillusa.com/ This might throw some light on it