Brave

Brave is a Chromium-based browser that blocks ads and trackers by default. Its source code is public, and it runs on desktop and mobile. Chrome extensions generally work in it.

Its AI assistant is called Leo. It sits in a sidebar and can summarize the current page, answer questions about it, or chat without page context. Brave says it does not keep Leo conversations to train models, and a paid tier adds access to more models and higher limits. Brave also runs its own search engine, which can show AI-written answers above the results.

Things to check: which model Leo is using for a given chat, whether page content is being shared with the assistant for that request, and how the paid tier handles your data compared with the free one.