feat: document data store

astro.sidebar.ts

@@ -163,6 +163,7 @@ export const sidebar = [
 					'reference/experimental-flags/content-intellisense',
 					'reference/experimental-flags/chrome-devtools-workspace',
 					'reference/experimental-flags/svg-optimization',
+					'reference/experimental-flags/collection-storage',
 				],
 			}),
 			'reference/legacy-flags',

src/content/docs/en/reference/experimental-flags/data-store.mdx

@@ -0,0 +1,36 @@
+---
+title: Experimental collection storage
+sidebar:
+  label: Collection storage
+i18nReady: true
+---
+
+import Since from '~/components/Since.astro'
+
+<p>
+
+  **Type:** `"single-file" | "chunked"`<br />
+  **Default:** `"single-file"`<br />
+  <Since v="7.1.0" />
+</p>
+
+This experimental feature allows you to change how content collections' data is stored. 
+
+By default, Astro stores this data in a single file at `.astro/data-store.json`. When set to `"chunked"`, Astro splits the data across multiple files inside the `.astro/data-store/` folder.
+
+```js title="astro.config.mjs" ins={5}
+import { defineConfig } from "astro/config";
+
+export default defineConfig({
+  experimental: {
+    collectionStorage: "chunked"
+  }
+});
+```
+
+In chunked mode, files are split across multiple chunks. Astro creates a new chunk when:
+
+- the current chunk reaches 1,000 entries;
+- the current chunk is larger than 10 MB.
+
+This option is recommended when deploying to platforms that have a size limit for individual assets.