Examples of discoveries that would have counted if they weren’t already made: Relativity (say a derivation of E=mc^2), Quantum Mechanics (say a calculation of the hydrogen energy levels), the discovery of Riemmannian geometry, the discovery of DNA, and the discovery of the theory of evolution with natural selection.
The idea is to test the system’s out of distribution generalization: its ability to achieve tasks that are beyond its training distribution. This is something that humans can do, but no current LLM appears to be able to do.