Jun 15, 2006 05:41 PM|DotNetSteve2005|LINK
This is from .Net 2.0 help file:
Browser definition files contain definitions for individual browsers. At run time, ASP.NET uses the information in the request header to determine what type of browser has made the request. Then ASP.NET uses .browser files to determine the capabilities of
the browser, and how to render markup to that browser. This is useful to Web developers who want to create applications that can be viewed on mobile devices, making use of control adapters that adapt the behavior of an ASP.NET Web server control depending
on the type of device.
Look under the headin browser capabilities