Edge Cache TTL (Time to Live) specifies the maximum time to cache a resource in the Cloudflare global network. Edge Cache TTL is not visible in response headers and the minimum Edge Cache TTL depends on plan type.| Cloudflare Docs
The Hypertext Transfer Protocol (HTTP) is a stateless \%application- level protocol for distributed, collaborative, hypertext information systems. This document defines HTTP caches and the associated header fields that control cache behavior or indicate cacheable response messages.| IETF Datatracker
Cloudflare respects the origin web server’s cache headers in the following order unless an Edge Cache TTL cache rule overrides the headers. Refer to the Edge TTL section for details on default TTL behavior.| Cloudflare Docs