QUESTION.txt is the user prompt from the user to the model.
ANSWER.base_system_prompt.txt is a sample response from Gemini with no
System Instructions applied (i.e. the box is blank).
Note that test-cases may be out-of-date and might not reflect the very latest engine improvements. I usually add new test-cases with changes to the prompt but don't yet have a strategy to re-run / re-evaluate the older test-cases.