Knowledge graph license

The knowledge graphs in this repository are licensed under the Creative
Commons Attribution 4.0 International License (CC BY 4.0):
https://creativecommons.org/licenses/by/4.0/

Covered: every `.kg` file under `graphs/`, `legal/` and `axioms/`, the `.mmd`
diagrams drawn from them, and any other `.kg` knowledge file in the repository
that is not a benchmark. Knowledge should be accessible to everyone: use it,
change it, share it, sell what you build with it, in any format, as long as you
credit the source.

Attribution to give:

   Knowledge graphs from MARCO by DoTaeIn, https://github.com/DoTaeIn/Marco,
   CC BY 4.0

Not covered: the engine code (see LICENSE, the MARCO Engine License) and the
frozen benchmark sets under `data/benchmarks/`, which are part of the engine's
exams and stay under the engine license.

Graphs published in this repository before 2026-09-24 were under the Apache
License, Version 2.0; copies received then remain under it.
