there are several ways to eliminate oxygen from the copper including vacuum techniques. The elimination of the oxygen improves conductivity. Nickel plating the copper also improves the life of the cable.Oxygen free refers to the elimination of oxygen when the copper is made not from the airspace in the cable.
This is handy for your copper not oxidizing internally although, I gather this takes some time to occur.
In any case, I can't see how getting that oxygen out WOULDN'T be a good thing.
If Manhattan project work is any indication, silver cables would be better. Ime, silver has problems that the cost do not address.
I like my Gibson brand cable. It's labeled instrument. And amp. The instrument end has a wooden cover on the plug end.
