Firefox 95 brings reduced power usage and CPU usage on macOS, as well as a couple security features. To better protect Firefox users against side-channel attacks such as Spectre, Site Isolation is now enabled for all Firefox 95 users. RLBox — a new technology that hardens Firefox against potential security vulnerabilities in third-party libraries — is now enabled on all platforms.
Check It Out: Firefox 95 Update Reduces CPU Usage and Power Usage on Mac