Not the same thing, but they have something close (it's not on-by-default, yet) [1]:

> Cloudflare's network now supports real-time content conversion at the source, for enabled zones using content negotiation headers. Now when AI systems request pages from any website that uses Cloudflare and has Markdown for Agents enabled, they can express the preference for text/markdown in the request. Our network will automatically and efficiently convert the HTML to markdown, when possible, on the fly.

[1] https://blog.cloudflare.com/markdown-for-agents/