Worked on the mullvad/mullvadvpn-app repository to deliver a configuration-based opt-in feature for Memory Tagging Extension (MTE) asynchronous mode. This addition allowed users to enable enhanced memory tagging through a configuration setting, while ensuring that the core application behavior remained unchanged unless explicitly activated. The implementation focused on system programming in C and leveraged configuration management principles to provide a safe, non-breaking path for testing and security hardening. All changes were clearly documented for future audits, establishing a foundation for further security enhancements and controlled feature rollout without impacting existing users or introducing regressions into the application’s core functionality.