[v6] trailing slash never for endpoints with file extension

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

@@ -89,6 +89,8 @@
 
 ### Vite 7.0
 
+<SourcePR number="14445" title="feat: update vite"/>
+
 Astro v6.0 upgrades to Vite v7.0 as the development server and production bundler.
 
 #### What should I do?
@@ -287,6 +289,8 @@
 
 ### Changed: `i18n.routing.redirectToDefaultLocale` default value
 
+<SourcePR number="14406" title="feat(astro)!: update i18n.redirectToDefaultLocale default"/>
+
 In Astro v5.0, the `i18n.routing.redirectToDefaultLocale` default value was `true`. When combined with the `i18n.routing.prefixDefaultLocale` default value of `false`, the resulting redirects could cause infinite loops.
 
 In Astro v6.0, `i18n.routing.redirectToDefaultLocale` now defaults to `false`. Additionally, it can now only be used if `i18n.routing.prefixDefaultLocale` is set to `true`.
@@ -309,6 +313,26 @@
 ```
 
 <ReadMore>Learn more about [Internationalization routing](/en/guides/internationalization/#routing).</ReadMore>
+value
+
+### Changed: endpoints with a file extension cannot be accessed with a trailing slash
+
+<SourcePR number="14457" title="feat!: trailing slash never for endpoints with file extension"/>
+
+In Astro v5.0, endpoints with a pathname ending with a file extension (eg. `/src/pages/sitemap.xml.ts`) could be accessed with a trailing slash (`/sitemap.xml/`) or without (`/sitemap.xml`), no matter the value of `build.trailingSlash`.
+
+In Astro v6.0, these endpoints can only be accessed without a trailing slash.
+
+#### What should I do?
+
+Review your links and remove any referencing an endpoint ending witha file a file extension and a trailing slash:
+
+```html del={1} ins={2} title="src/pages/index.astro"
+<a href="/sitemap.xml/">Sitemap</a>
+<a href="/sitemap.xml">Sitemap</a>
+```
+
+<ReadMore>Learn more about [`build.trailingSlash`](https://docs.astro.build/en/reference/configuration-reference/#trailingslash).</ReadMore>
 
 ## Breaking Changes