Certificate Transparency (CT) has been crucial for web security, combating threats like certificate fraud and man-in-the-middle attacks. Firefox is taking significant steps by enforcing CT on desktop platforms with version 135. This ensures only CT-compliant certificates are trusted, enhancing transparency standards. Website owners should ensure their CA supports CT logging and monitor certificates using monitoring tools to prevent unauthorized certificates. Firefox requires signed certificate timestamps (SCTs) for connections to succeed. Known trusted CT logs are automatically updated in Firefox each week. Firefox may support tile-based logs in the future. Overall, CT enforcement in Firefox enhances web security, making browsing safer for users.
https://blog.transparency.dev/ct-in-firefox