Modify FileSystemTree Controller - that if * is used for file extension then we will return all files :)

src/Umbraco.Web/Trees/FileSystemTreeController.cs

@@ -57,6 +57,10 @@ namespace Umbraco.Web.Trees
             var files = FileSystem.GetFiles(path).Where(x =>
             {
                 var extension = Path.GetExtension(x);
+
+                if (Extensions.Contains("*"))
+                    return true;
+                
                 return extension != null && Extensions.Contains(extension.Trim('.'), StringComparer.InvariantCultureIgnoreCase);
             });
 

src/Umbraco.Web/Trees/FilesTreeController.cs

@@ -10,9 +10,11 @@ namespace Umbraco.Web.Trees
     {
         protected override IFileSystem FileSystem => new PhysicalFileSystem("~/"); // fixme inject
 
-        protected override string[] Extensions => new string[] { };
+        private static readonly string[] ExtensionsStatic = { "*" };
 
-        protected override string FileIcon => "icon-script";
+        protected override string[] Extensions => ExtensionsStatic;
+
+        protected override string FileIcon => "icon-document";
 
         protected override void OnRenderFolderNode(ref TreeNode treeNode)
         {