Third-party notices
The CARGB firmware is built on open-source work by other people. There are 388 such components, mostly under the MIT and Apache-2.0 licences, and both of those require that the authors’ copyright notices travel with the software. This is where they are.
Each component stays under its own licence. Neither the firmware licence nor the simulator licence restricts what you may do with them — go to the component’s own project for that.
The website
This site is built on other people’s work too: 577 npm packages, the Michroma and Oxanium typefaces under the SIL Open Font Licence, and the built-in car meshes, which are public domain. That list is generated from the installed dependency tree, so it cannot fall behind what is actually here.
The same file ships as THIRD-PARTY-NOTICES.md in every firmware release package. It is not stored on the controller itself — at this size it would not fit alongside the firmware.