In VS2015, I've recently been getting an XML comment added to my web.config file for website projects that I publish:
<!--ProjectGuid: CDCD60A4-F8AC-4343-A798-8B9917B7711D-->
This only happens when my project has a web.config transform file in effect (Web.Debug.config or a Web.Release.config).
I tried scouring the interweb but the only thing I found was in reference to dealing with the presence of the comment: https://github.com/projectkudu/kudu/issues/2064.
It's obviously not functionally an issue, but since we have multiple developers publishing this project at different times to our version control system, and only my system seems to be adding this line, it's going to cause a lot of commit noise.