Update note on the NotFound param (#34389)

Author: guardrex

aspnetcore/blazor/components/render-modes.md

@@ -380,7 +380,7 @@ During static SSR, Razor component page requests are processed by server-side AS
 
 * [Not authorized content (`<NotAuthorized>...</NotAuthorized>`)](xref:blazor/security/index#authorizeview-component) (<xref:Microsoft.AspNetCore.Components.Authorization.AuthorizeRouteView.NotAuthorized>): Blazor Web Apps typically process unauthorized requests on the server by [customizing the behavior of Authorization Middleware](xref:security/authorization/authorizationmiddlewareresulthandler).
 
-* [Not found content (`<NotFound>...</NotFound>`)](xref:blazor/fundamentals/routing#provide-custom-content-when-content-isnt-found) (<xref:Microsoft.AspNetCore.Components.Routing.Router.NotFound>): Blazor Web Apps typically process bad URL requests on the server by either displaying the browser's built-in 404 UI or returning a custom 404 page (or other response) via ASP.NET Core middleware (for example, [`UseStatusCodePagesWithRedirects`](xref:fundamentals/error-handling#usestatuscodepageswithredirects) / [API documentation](xref:Microsoft.AspNetCore.Builder.StatusCodePagesExtensions.UseStatusCodePagesWithRedirects%2A)).
+* [Not found content (`<NotFound>...</NotFound>`)](xref:blazor/fundamentals/routing#provide-custom-content-when-content-isnt-found) (<xref:Microsoft.AspNetCore.Components.Routing.Router.NotFound>): Blazor Web Apps typically process bad URL requests on the server by either displaying the browser's built-in 404 UI or returning a custom 404 page (or other response) via ASP.NET Core middleware (for example, [`UseStatusCodePagesWithRedirects`](xref:fundamentals/error-handling#usestatuscodepageswithredirects) / [API documentation](xref:Microsoft.AspNetCore.Builder.StatusCodePagesExtensions.UseStatusCodePagesWithRedirects%2A)). For more information, see [Create simpler way to show Not Found 404 UI with Blazor (`dotnet/aspnetcore` #45654)](https://github.com/dotnet/aspnetcore/issues/45654).
 
 If the app exhibits root-level interactivity, server-side ASP.NET Core request processing isn't involved after the initial static SSR, which means that the preceding Blazor features work as expected.
 

aspnetcore/blazor/fundamentals/routing.md

@@ -156,7 +156,11 @@ Arbitrary items are supported as content of the <xref:Microsoft.AspNetCore.Compo
 :::moniker range=">= aspnetcore-8.0"
 
 > [!IMPORTANT]
-> Blazor Web Apps don't use the <xref:Microsoft.AspNetCore.Components.Routing.Router.NotFound> parameter (`<NotFound>...</NotFound>` markup), but the parameter is supported for backward compatibility to avoid a breaking change in the framework. The server-side ASP.NET Core middleware pipeline processes requests on the server. Use server-side techniques to handle bad requests. For more information, see <xref:blazor/components/render-modes#static-server-side-rendering-static-ssr>.
+> Blazor Web Apps don't use the <xref:Microsoft.AspNetCore.Components.Routing.Router.NotFound> parameter (`<NotFound>...</NotFound>` markup), but the parameter is supported&dagger; for backward compatibility to avoid a breaking change in the framework. The server-side ASP.NET Core middleware pipeline processes requests on the server. Use server-side techniques to handle bad requests.
+>
+> &dagger;*Supported* in this context means that placing `<NotFound>...</NotFound>` markup doesn't result in an exception, but using the markup isn't effective either.
+>
+> For more information, including a recommended approach for handling bad requests, see <xref:blazor/components/render-modes#static-server-side-rendering-static-ssr>.
 
 :::moniker-end