Skin files, introduced in ASP.NET 2.0, make it easier to specify an application’s look and feel. Commercial developers will want to add a comment with their copyright notice, but Microsoft does not explain how to put a comment in a skin file. In his book “Programming ASP.NET 2.0 Core Reference,” Dino Esposito shows skin file content with an HTML comment, but that will cause a build failure in the release version of Visual Studio 2005.
Although a skin file looks like .aspx markup, it is highly restricted. However, it does recognize ASP code blocks and will accept code block comments, such as this example:
< % – – Copyright 2006 XYZ Corp. All rights reserved. – – % >
[Note: because of display limitations, characters "" here are shown with a space after or before them.]
– copied from http://aspnet2holes.blogspot.com/2006/06/comments-in-skin-file.