They were under NDA, probably
But the science was probably not
I don't think this is classified technology, although asml would like it if they were punished.
And even if it's patented, China has been stealing everything with little consequence
Patent system is an abomination anyway.
One interesting and ironic part of the article is that one of the mentioned optics research groups has been submitting a lot of patents on EUV sources. Are we meant to be mad about it?