In reply to Miroslav Glavic.

@Chip Bennett,

But then, I believe that a sane court would hold that Themes and Plugins, absent actual, incorporated code from core WordPress, are not derivative works. So I’m already in the minority with respect to opinions about how courts would rule.

You can add me to your minority! In fact, I think we're in the minority only among the Tavern/WordPress community. I think the overwhelming majority of lawyers would agree with everything you've said here.