Had to look 'cunifer line' up. Interesting composition as it seems to have a bit of iron in it and on occasion a tiny bit of magnesium.
I also found this and thought I"d share:
Description
Why Some Brake Shops Refuse To Carry Copper Nickel Tube
There are brake shops who WILL NOT carry Copper Nickel tubing, can you guess why?
Is it a safety issue?
Nope Copper nickel tubing meets the definitive SAE J1047 standard. It’s approved for automotive use including brake lines and passes inspection
Ok well then it must be a bitch to work with?
Nope. This tubing is a breeze to work with and can be bent by hand. If anything it bends so easy you’ll have to make sure you helper doesn’t bend it for fun when they should be holding the light. It’s that easy and almost fun to bend.
Does it look bad?
Nope copper nickel tubing is an attractive alternative to grungy steel lines and can even be polished to shine.
Is it weird and non standard?
Nope Copper nickel tubing is standard on Aston Martin, Porche, or other high end luxury cars.
Then it must require special high priced fittings to work?
Nope again. This tubing is the same size and operates using the exact same hardware as your existing lines. If you want to reuse your old nuts and fittings you can, and your new tubing will put them to shame with how nice it looks.
The Real Reason
Brake Shops tell us they don’t want to use Copper Nickel Tubing because it means YOU WILL NEVER COME BACK for more tubing work. They don’t like the thought of putting something on your car that will result in no chance of future business.
Especially in the northern US where every year road salt eats away at your steel lines. They know that you’ll be back and they can rack up more labor charges. They know that with rigid steel tube you won’t be working on your own lines without the help of expensive handling tools.
How many times do you want to replace your lines?
Do you want to replace the line once and for all? Do you want to enjoy recreating your existing lines without the use of expensive bending tools? Do you want to invest in the same materials high end manufacturers already use?