Rule 4: "Create a new public GitHub repository to store the source code and any assets you’re able to share for your entry and push your changes before December 1 13:37 PT."
My read is that you don't need to share any third-party assets (e.g. stuff you buy on itch.io) if their license doesn't allow it. But your code, your own assets, and any third-party assets you *are* allowed to share (e.g. kenney's CC0-licensed stuff) need to go into the git repo.
