“compat.browser” within the server’s IIS directory will be "\inetpub\wwwroot\wss\VirtualDirectories\80\App_Browsers\compat.browser").
The configuration file for sharepoint 2010 with Mobiles. For eg. The IsMobileDevice attribute of that mobile browser when set to FALSE will
cause SharePoint to bypass the mobile view for that browser.”
Note that if you do any modification with sharepoint designer to a site and found that *.browser file got duplicated in another folder , you need to delete this folder