Worked on stabilizing TLS certificate handling in the Prinzhorn/mitmproxy repository, focusing on resolving a persistent AttributeError in the certificate management workflow. Addressed the issue by ensuring that CertStore consistently stores Cert objects rather than raw x509.Certificate objects, converting certificates as needed before storage. This Python-based fix improved the reliability of certificate processing across proxy chains, reducing errors and downtime for both clients and upstream connections. The work demonstrated attention to traceability by linking the solution to relevant issues, and contributed to more maintainable TLS infrastructure by eliminating a class of certificate handling errors in the proxy’s core logic.