Add native auth feature to support the external ID authentication (sign-in, sign-up and SSPR) (#7599)

CODEOWNERS

@@ -6,6 +6,7 @@
 
 # MSAL Browser
 /lib/msal-browser/ @sameerag @tnorling @hectormmg @jo-arroyo @peterzenz @konstantin-msft @lalimasharda @shylasummers
+/lib/msal-browser/custom-auth @shenj @yongdiw
 /samples/msal-browser-samples/ @sameerag @tnorling @hectormmg @jo-arroyo @peterzenz @konstantin-msft @lalimasharda @shylasummers
 
 # MSAL Common

README.md

@@ -18,6 +18,13 @@ The [`lib`](https://github.com/AzureAD/microsoft-authentication-library-for-js/t
     -   [On-behalf-of Flow](https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-on-behalf-of-flow)
 
 -   [Microsoft Authentication Library for JavaScript](lib/msal-browser/): A browser-based, framework-agnostic browser library that enables authentication and token acquisition with the Microsoft Identity platform in JavaScript applications. Implements the OAuth 2.0 [Authorization Code Flow with PKCE](https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-auth-code-flow), and is [OpenID-compliant](https://docs.microsoft.com/azure/active-directory/develop/v2-protocols-oidc).
+
+-   [Native Authentication Support for JavaScript](lib/msal-browser/src/custom_auth/): MSAL also provides native authentication APIs that allow applications to implement a native experience with end-to-end customizable flows in their applications. With native authentication, users are guided through a rich, native, sign-up and sign-in journey without leaving the app. The native authentication feature is available for SPAs on [External ID for customers](https://learn.microsoft.com/en-us/entra/identity-platform/concept-native-authentication). It is recommended to always use the most up-to-date version of the SDK.
+
+    > **Note:** The native authentication feature is currently in preview and is not considered production-stable. Features and APIs may change before general availability.
+    >
+    > **Terminology:** In the codebase, the term "Custom Auth" is used instead of "Native Auth". You will find classes, interfaces, and configuration options prefixed with `CustomAuth` (e.g., `CustomAuthPublicClientApplication`, `CustomAuthConfiguration`). Please refer to these when implementing or exploring the native authentication feature in the code.
+
 -   [Microsoft Authentication Library for React](lib/msal-react/): A wrapper of the msal-browser library for apps using React.
 -   [Microsoft Authentication Library for Angular](lib/msal-angular/): A wrapper of the msal-browser library for apps using Angular framework.
 -   [Microsoft Authentication Extensions for Node](extensions/msal-node-extensions/): The Microsoft Authentication Extensions for Node offers secure mechanisms for client applications to perform cross-platform token cache serialization and persistence. It gives additional support to the Microsoft Authentication Library for Node (MSAL).

change/@azure-msal-browser-3240f33d-ab3b-4b05-9d0f-816c70517f13.json

@@ -0,0 +1,7 @@
+{
+  "type": "minor",
+  "comment": "Add native authentication feaetures for the external ID",
+  "packageName": "@azure/msal-browser",
+  "email": "shen.jian@live.com",
+  "dependentChangeType": "patch"
+}