We just shipped support for the ugliest part of HTTP: Vary – Cloudflare Blog
Cloudflare has added support for the HTTP Vary header, enabling better caching of responses that vary by request headers. The update addresses a long‑standing limitation in the platform’s edge caching logic. By honoring Vary, Cloudflare can now store distinct cached versions for different user agents, languages, or other header values, improving cache hit rates and content delivery.