What's a Permissive License – and Why Should I Care?

> everyone who contributes to a GNU GPL, licensed project, or creates a derivative work of a GNU GPL licensed project, must upstream their contribution – without exception.

That's entirely untrue. There is no such requirement in the GPL. Further, any license with such a requirement would be non-free. Since this whole article revolves around that point, it should be entirely discounted.

"free as in free puppies, or free as in beer"? I've never heard that, and they're selling themselves short, if they redefine gratis as "no strings attached".

Let's just go full ironic-Heinlein and say "free as in lunch"!