Out of the blue come the System Reference Document under Open Gaming License from for Dungeons & Dragons 5th edition.
You can find the pdf files here: SRD 5th
This mean you can produce supplements for D&D 5th edition on your own, or your derivative game as happened for d20 products.
Maybe the authors of 5th edition wanted to secure the rules for fan in case WOTC stops supporting to the game.... but it's such a great news!
NEWS: now also in Italian! Here: SRD 5E Italy