[next]: stabilize failOnPrerenderConflict

astro.sidebar.ts

@@ -148,7 +148,6 @@ export const sidebar = [
 					'reference/experimental-flags/client-prerender',
 					'reference/experimental-flags/content-intellisense',
 					'reference/experimental-flags/chrome-devtools-workspace',
-					'reference/experimental-flags/fail-on-prerender-conflict',
 				],
 			}),
 			'reference/legacy-flags',

src/content/docs/en/guides/upgrade-to/v6.mdx

@@ -291,7 +291,6 @@ const { Content, headings } = await render(post);
 
 <ReadMore> See [the Astro v5 upgrade guide](/en/guides/upgrade-to/v5/#legacy-v20-content-collections-api) for previous guidance about backwards compatibility of legacy collections in Astro v5 and full step-by-step instructions for upgrading legacy collections to the new Content Layer API.</ReadMore>
 
-
 ### Removed: `<ViewTransitions />` component
 
 <SourcePR number="14400" title="Remove deprecated ViewTransitions component"/>
@@ -554,7 +553,7 @@ Experimental flags allow you to opt in to features while they are in early devel
 
 Remove these experimental flags from your Astro config if you were previously using them:
 
-```js del={5-8} title="astro.config.mjs"
+```js del={5-9} title="astro.config.mjs"
 import { defineConfig } from 'astro/config';
 
 export default defineConfig({
@@ -563,13 +562,15 @@ export default defineConfig({
     preserveScriptOrder: true,
     staticImportMetaEnv: true,
     headingIdCompat: true,
+    failOnPrerenderConflict: true
   },
 })
 ```
 
 #### Experimental features now stable:
 
 - `liveContentCollections` (See the updated [content collections docs](/en/guides/content-collections/) to learn more about live collections.)
+- `failOnPrerenderConflict` (See the new [`prerenderConflictBehavior`](/en/reference/configuration-reference/#prerenderconflictbehavior) configuration option.)
 
 #### New default or recommended behavior:
 
@@ -579,7 +580,6 @@ export default defineConfig({
 
 <ReadMore>Read about exciting new features and more in [the v6.0 Blog post](https://astro.build/blog/astro-6/).</ReadMore>
 
-
 ## Changed Defaults
 
 Some default behavior has changed in Astro v5.0 and your project code may need updating to account for these changes.

src/content/docs/en/reference/configuration-reference.mdx

@@ -366,6 +366,27 @@ Using `'class'` is helpful when you want to ensure that element selectors within
 Using `'where'` gives you more control over specificity, but requires that you use higher-specificity selectors, layers, and other tools to control which selectors are applied.
 Using `'attribute'` is useful when you are manipulating the `class` attribute of elements and need to avoid conflicts between your own styling logic and Astro's application of styles.
 
+### prerenderConflictBehavior
+
+<p>
+
+**Type:** `'error' | 'warning' | 'default'`<br />
+**Default:** `'warning'`<br />
+<Since v="6.0" />
+</p>
+
+Determines the default behavior when two routes generate the same prerendered URL:
+
+  - `error`: fail the build and display an error, forcing you to resolve the conflict
+  - `warning` (default): log a warning when conflicts occur, but build using the highest-priority route
+  - `ignore`: silently build using the highest-priority route when conflicts occur
+
+```js
+{
+  prerenderConflictBehavior: 'error'
+}
+```
+
 ### security
 
 <p>