What are the WCF Service Reference .datasource files?

What are the .datasource files that are automatically generated by "Create Service Reference" in Visual Studio? The comment in the file is this:

This file is automatically generated by Visual Studio .Net. It is used to store generic object data source configuration information.
Renaming the file extension or editing the content of this file may
cause the file to be unrecognizable by the program.

However, it sounds like these files are optional, so I'm wondering what they are used for. I'm also wondering if it is truly safe to delete them, since they often cause path length problems on XP.

http://www.eggheadcafe.com/conversation.aspx?messageid=34104031&threadid=34104026

Can anyone point me to some official MS documentation on these files?

As far as I remember, they are just generated so that you can use the data contracts used in the service as object data sources for data binding against UI controls.

The .datasource files are optional, but they can be used in your client app to easily bind a data contract to a ui control. Here is an article explaining how to use them:

http://msdn.microsoft.com/en-us/library/ee373840.aspx

I was able to delete them from one of our projects. Project built fine, and loaded stuff from the database fine, so I'm assuming it was safe. I would like to hear someone who knows more about them weigh in on this element of the subject though.