This is an Angular SDK library (`@auth0/auth0-angular`) that integrates Auth0 authentication (OAuth2/OIDC) into Angular single-page applications. It wraps the Promise-based `@auth0/auth0-spa-js` into Angular's reactive ecosystem using RxJS Observables, dependency injection, and Angular Router. The library provides core authentication flows (redirect/popup login, logout, token management), route protection via guards, automatic bearer token injection via HTTP interceptors, and additional features such as MFA, passkeys (WebAuthn), enterprise account linking, custom token exchange, and a MyAccount API client. It supports both traditional NgModule-based and modern standalone (functional) Angular patterns. The playground application included serves as a development and e2e test harness with a local OIDC provider. The architecture is clean, well-tested, and follows Angular best practices, though the core logic is delegated to the underlying Auth0 SPA SDK.