Wizards has just published the new Game System License and the new System Reference Document at wizards.com/d20.

Here’s the important part of the GSL- from section 5.5, Licensed Products

For the avoidance of doubt, and by way of example only, no Licensed Product will (a) include web sites, interactive products, miniatures, or character creators; (b) describe a process for creating a character or applying the effects of experience to a character; (c) use the terms “Core Rules” or “Core Rulebook” or variations thereof on its cover or title, in self-reference or in advertising or marketing thereof; (d) refer to any artwork, imagery or other depiction contained in a Core Rulebook; (e) reprint any material contained in a Core Rulebook except as explicitly provided in Section 4; or (f) be incorporated into another product that is itself not a Licensed Product (such as, by way of example only, a magazine or book compilation).

Note that this does not discriminate between Licensed Products that are for sale or free.  Effectively, things like Heroforge are no-gos.

Remember that poison pill clause thing everyone was buzzing about this spring?  Here’s the bit that fills that billet.

No Backward Conversion. Licensee acknowledges and agrees that it will not publish any product pursuant to the OGL that features the same or similar title, product line trademark, or contents of a Licensed Product.

The new SRD is, as they stated earlier, merely a reference to what is in the current rules. Here are a couple of the salient paragraphs from the SRD -

Use the stat block templates identified and included in the SRD as guidelines (not constraints) for producing your own original content requiring such formatting. Since your content will resemble like content in the Core Rulebooks, it will be more readily usable. You may not reproduce the blank stat block templates included in the SRD in a Licensed Product.

To remain in compliance with the GSL, you may not reproduce any running text, statistics block, or table from the Core Rulebooks, nor may you define, redefine, or alter the definition of any 4E Reference. Nothing in these guidelines should be taken as contrary to these GSL requirements. ...

Rules Influence
While you may not reproduce running text and tables from the Core Rulebooks, you may create original material that reflects the influence of rules and guidelines in the Core Rulebooks.

For instance, you may create powers that resemble those in D&D 4E Player’s Handbook. You may use the guidelines in Chapter 6: Adventures of the D&D 4E Dungeon Master’s Guide to influence how you create your own adventures. Similarly, you may use the rules for Treasure Parcels (D&D 4E Dungeon Master’s Guide, page 126) to create treasure hoards in your adventure.

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