What should I do if I suspect a DDoS attack is targeting my GitHub repository's associated services (e.g., a linked web server)?

Immediately contact your hosting provider and GitHub Support. Implement DDoS mitigation techniques on your linked web server, such as using a WAF, CDN, and rate limiting. Analyze your server logs to identify the source of the attack and block malicious IP addresses. Consider engaging a DDoS mitigation service for more comprehensive protection.