Document cache_option_preserves_cache_control compatibility flag

src/content/compatibility-flags/cache-option-preserves-cache-control.md

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+---
+name: "`cache` option does not override the origin's `Cache-Control`"
+sort_date: "2026-11-17"
+enable_date: "2026-11-17"
+enable_flag: "cache_option_preserves_cache_control"
+disable_flag: "cache_option_overrides_cache_control"
+---
+
+When you enable the `cache_option_preserves_cache_control` compatibility flag, setting the `cache`
+property of the Request interface to `no-cache` or `no-store` no longer overrides the
+`Cache-Control` header of the origin's response when Cloudflare caches it.
+
+Per the [Fetch standard](https://fetch.spec.whatwg.org/#concept-request-cache-mode), a request's
+cache mode controls how the cache may use a stored response. It does not control how the response
+may be cached:
+
+- `no-cache` forces Cloudflare's cache to revalidate with the origin.
+- `no-store` bypasses Cloudflare's cache.
+
+Without this flag, `cache: 'no-cache'` also caches the response as if the origin had sent
+`Cache-Control: no-cache`, and `cache: 'no-store'` as if it had sent `Cache-Control: no-store`.
+For example, with `cache: 'no-cache'`, a response the origin marked `Cache-Control: no-store` is
+cached as `no-cache`.
+
+With this flag, the origin's `Cache-Control` is respected:
+
+```js
+// Revalidates with the origin; the response is cached according to the origin's Cache-Control.
+const response = await fetch("https://example.com", { cache: "no-cache" });
+```
+
+To override the origin's `Cache-Control`, omit the `cache` option and set
+[`cf.cacheControl`](/workers/runtime-apis/request/#the-cf-property-requestinitcfproperties)
+instead:
+
+```js
+const response = await fetch("https://example.com", {
+	cf: { cacheControl: "no-cache" },
+});
+```