The ABB SrcML service provides analysis services for other visual studio extensions to consume. In order to develop against the SrcML service, you must download and installSrcML.NET (also available on nuget). The SrcML service provides analysis data for C, C++, C#, and Java.
You can see an example of the SrcML Service working by looking at Sando, a code search tool for Visual Studio that uses the SrcML Service to get notified of file changes.
For more information on the SrcML XML format, see srcml.org.
You probably don't want to download the SrcML Service unless you're developing visual studio extensions. Please get in touch on thedeveloper forum to see what the SrcML Service can do.