Currently the FileExplorer control uses the file extension to determine what icon to show beside the file name. If you hide the file extensions on the server, it will also cause all files to use the "default" icon. If you are fine with this behavior, then you can override the default FileSystemContentProvider
and its ResolveRootDirectoryAsTree
methods. This will give you control over the files and folders displayed in the FileExplorer and you will be able to remove the file extensions from the file names.
the Telerik team