The syllabus for the Ethics, Integrity, and Aptitude paper in the UPSC Mains examination includes key themes such as ethical theories, integrity in public service, the concept of probity, and the significance of emotional intelligence. Candidates are assessed on their understanding of ethical dilemmas, principles of good governance, and the ways to apply ethical reasoning in real-life situations. Case studies may also be included to gauge how candidates would act in various scenarios related to civil services.