[cdibona]

So once you reduce the remaining pieces of the ship to api calls or interfaces or simply constant definitions, you'll find that copyright still attaches, but that's okay.

The whole point of the final rulings in the oracle/google trial is that is indeed copywritten by the author, but fair use. So source code stanzas that are ...well...totally banal or generic aren't actually suddenly not covered by copyright, but the argument you'd make (after fourteen years in court in googles case) is that it is fair use, wether that copyright is under open source or proprietary licenses.

There isn't a magical ability to declare something a derivative work when it isn't, just because it's open source/copyleft.

That said, when engineers or pms came to me asking to remove copyright attribution, I almost always said no.