I'm going through some ms source code and ran into the two using directives:
- sing SR=MS.Internal.PresentationCore.SR;
- using SRID=MS.Internal.PresentationCore.SRID;
Can't find anything using with Google or Bing. My first guess is that they are there to keep people from mindlessly reusing ms code. I ran into them reading the GlyphRun class source code. Namespace: System.Windows.Media