Here is a previous discussion of the same issue with banner / licensing:
That paragraph beginning “A story file produced with the Inform system belongs” appears on the copyright page of the Inform 6 Designers Manual (2001), and I believe it is called “the Inform License” – I know it was long bundled with Inform 6 as license.txt. Oddly there is no such license document on the Mac side of Inform 7 (that I can find) – not in the official download DMG, or in Inform.app, or project folders, or exported works, or available for lookup through the documentation search bar. Inform.app does contain a copy of the RegexKitLite License.rtf, but that is it. The two places where the word “license” appears on inform7.com are a discussion of licensing extensions and the licensing of recipes in the recipe book.
The Inform7 Wikipedia Page says “Proprietary but freely redistributable or Artistic License 2.0” – but I also couldn’t find a copy of that license included anywhere with Inform 7 either. The “Opening Inform” talk says that it will be used for a future release. The Wikipedia page may just be referring to the fact that the bundled Inform 6 core is available under that license – or that Wikipedia editors may have been getting ahead of themselves.
Anyway, hard to suss out.