title: Retrieve Source Settings from custom TFS Activity
body: <p>In a custom TFS activity, I am trying to get access to the following value defined in my build  definition.</p>
  
  <p><img src="https://i.stack.imgur.com/EGto5.png" alt="enter image description here"></p>
  
  <p>Where is this stored?  I can't see it in an Environment Variable.  I also looked all over the IBuildDetail retrieved with a Microsoft.TeamFoundation.Build.Workflow.Activities.GetBuildDetail activity, but I am not able to find the value anywhere.</p>
  
  <p>I need this before the sources are retrieved.</p>
  
  <p>Can someone help?  Much thanks!</p>