In the current version B12, page 53 (and on), a lot of references to @current_user are no longer valid as even Phoenix LiveView 1.8 guidelines state that this has changed. From AGENTS.md file:

<!-- phoenix-gen-auth-start -->
## Authentication

- **Always** handle authentication flow at the router level with proper redirects
- **Always** be mindful of where to place routes. `phx.gen.auth` creates multiple router plugs and `live_session` scopes:
  - A plug `:fetch_current_user` that is included in the default browser pipeline
  - A plug `:require_authenticated_user` that redirects to the log in page when the user is not authenticated
  - A `live_session :current_user` scope - For routes that need the current user but don't require authentication, similar to `:fetch_current_user`
  - A `live_session :require_authenticated_user` scope - For routes that require authentication, similar to the plug with the same name
  - In both cases, a `@current_scope` is assigned to the Plug connection and LiveView socket
  - A plug `redirect_if_user_is_authenticated` that redirects to a default path in case the user is authenticated - useful for a registration page that should only be shown to unauthenticated users
- **Always let the user know in which router scopes, `live_session`, and pipeline you are placing the route, AND SAY WHY**
- `phx.gen.auth` assigns the `current_scope` assign - it **does not assign a `current_user` assign**.
- To derive/access `current_user`, **always use the `current_scope.user` assign**, never use **`@current_user`** in templates or LiveViews

Please update your examples because I would think a lot of people might get lost (I did, had to fix this to make it work)