Firefox adds a global AI opt-out checkbox:

Opting out of upcoming and current AI features on your browser should not require endless navigation through multiple Settings pages. That’s why Firefox offers an AI controls section within its General Settings panel. A single, easily located place where you can block current and future AI features and related pop-ups with the swipe of a toggle.

Kind of similar to Micro.blog’s AI checkbox, but the Firefox version is more complicated, allowing control of various AI-related features.