Remove HostBuilder UseUmbraco extension, it's not required.

src/Umbraco.Infrastructure/Composing/HostBuilderExtensions.cs

@@ -1,25 +0,0 @@
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
-
-namespace Umbraco.Core.Composing
-{
-    /// <summary>
-    /// Extends the <see cref="IHostBuilder"/> to add CoreRuntime as a HostedService
-    /// </summary>
-    public static class HostBuilderExtensions
-    {
-        /// <summary>
-        /// Adds CoreRuntime as HostedService
-        /// </summary>
-        /// <remarks>
-        /// Should be called before ConfigureWebDefaults.
-        /// </remarks>
-        public static IHostBuilder UseUmbraco(this IHostBuilder builder)
-        {
-            _ = builder.ConfigureServices((context, services) =>
-                  services.AddSingleton<IHostedService>(factory => factory.GetRequiredService<IRuntime>()));
-
-            return builder;
-        }
-    }
-}

src/Umbraco.Tests.Integration/RuntimeTests.cs

@@ -43,7 +43,6 @@ namespace Umbraco.Tests.Integration
             var testHelper = new TestHelper();
 
             var hostBuilder = new HostBuilder()
-                .UseUmbraco()
                 .ConfigureServices((hostContext, services) =>
                 {
                     var webHostEnvironment = testHelper.GetWebHostEnvironment();

src/Umbraco.Tests.Integration/Testing/UmbracoIntegrationTest.cs

@@ -153,7 +153,6 @@ namespace Umbraco.Tests.Integration.Testing
         public virtual IHostBuilder CreateHostBuilder()
         {
             var hostBuilder = Host.CreateDefaultBuilder()
-                .UseUmbraco()
                 // IMPORTANT: We Cannot use UseStartup, there's all sorts of threads about this with testing. Although this can work
                 // if you want to setup your tests this way, it is a bit annoying to do that as the WebApplicationFactory will
                 // create separate Host instances. So instead of UseStartup, we just call ConfigureServices/Configure ourselves,

src/Umbraco.Web.Common/Builder/UmbracoBuilderExtensions.cs

@@ -146,7 +146,9 @@ namespace Umbraco.Core.DependencyInjection
             builder.Services.AddUnique<IRuntimeState, RuntimeState>();
             builder.Services.AddUnique<IHostingEnvironment, AspNetCoreHostingEnvironment>();
             builder.Services.AddUnique<IMainDom, MainDom>();
+
             builder.Services.AddUnique<IRuntime, CoreRuntime>();
+            builder.Services.AddHostedService<IRuntime>(factory => factory.GetRequiredService<IRuntime>());
 
             builder.AddCoreInitialServices();
             builder.AddComposers();

src/Umbraco.Web.UI.NetCore/Program.cs

@@ -20,7 +20,6 @@ namespace Umbraco.Web.UI.NetCore
                 {
                     x.ClearProviders();
                 })
-                .UseUmbraco()
                 .ConfigureWebHostDefaults(webBuilder => { webBuilder.UseStartup<Startup>(); });
     }
 }