Add a breaking change doc about deep links flag change to the flutter website

src/content/release/breaking-changes/deep-links-flag-change.md

@@ -0,0 +1,68 @@
+---
+title: Deep links flag change
+description: >
+  If you use a third party deep linking plugin package for mobile apps,
+  set Flutter's deep linking flag to false.
+---
+
+## Summary
+
+<b>This (potential) breaking change only affects mobile apps and only if you
+use a third party deep linking plugin package.</b>
+
+The default value for Flutter’s deep linking flag has changed from `false` to `true`,
+meaning that deep linking is now opt-in by default.  
+
+## Migration guide
+
+
+If you’re using Flutter’s default deep linking setup, this is not a breaking change for you. 
+
+However, if you’re using a third-party plugin for deep links,
+such as the following, this update introduces a breaking change:
+
+[firebase dynamic links](https://firebase.google.com/docs/dynamic-links)
+[uni_link](https://pub.dev/packages/uni_links)
+[app_links](https://pub.dev/packages/app_links)
+
+In this case, you must manually reset the Flutter deep linking flag to `false`.
+
+Before: non-op
+
+After:
+
+Manually disable the deep linking flag if you use a third-party plugin:
+
+* Android Manifest file
+
+```yaml
+<manifest>
+   <application
+       <activity>
+<meta-data android:name="flutter_deeplinking_enabled" android:value="false" />
+       </activity>
+   </application>
+</manifest>
+```
+
+* iOS info.plist file
+
+```yaml
+   <key>FlutterDeepLinkingEnabled</key>
+   <false/>
+```
+
+## Timeline
+
+Landed in version: 3.27.0-0.0.pre<br>
+Stable release: 3.27
+
+## References
+
+Design documentation:
+flutter.dev/go/deep-link-flag-migration.
+
+Relevant PR:
+
+* [Set deep linking flag to true by defaulte]({{site.github}}/flutter/engine/pull/52350)
+

src/content/release/breaking-changes/index.md

@@ -54,6 +54,7 @@ release, and listed in alphabetical order:
 * [`Color` wide gamut support][]
 * [Remove invalid parameters for `InputDecoration.collapsed`][]
 * [Stop generating `AssetManifest.json`][]
+* [Deep links flag change][]
 * [Deprecate `TextField.canRequestFocus`][]
 * [Set default for SystemUiMode to Edge-to-Edge][]
 * [Material 3 Tokens Update in Flutter][]
@@ -62,6 +63,7 @@ release, and listed in alphabetical order:
 [`Color` wide gamut support]: /release/breaking-changes/wide-gamut-framework
 [Remove invalid parameters for `InputDecoration.collapsed`]: /release/breaking-changes/input-decoration-collapsed
 [Stop generating `AssetManifest.json`]: /release/breaking-changes/asset-manifest-dot-json
+[Deep links flag change]: /release/breaking-changes/deep-links-flag-change
 [Deprecate `TextField.canRequestFocus`]: /release/breaking-changes/can-request-focus
 [Set default for SystemUiMode to Edge-to-Edge]: /release/breaking-changes/default-systemuimode-edge-to-edge
 [Material 3 Tokens Update in Flutter]: /release/breaking-changes/material-design-3-token-update