I've made my own Visual Studio theme in the 2013 version and now I'm migrating to 2015. Since the font and color settings on XML Doc comments changed, I had to reconfigure the color for the XML comments. However, the color is not applied for the attributes values.
Here we can see it's black but supposed to be green.
Here's what the options look like:
Pretty much all the options starting with "XML" are set to green, so I suppose there's another manipulation to do ?
The value you are looking for is under Tools -> Options -> Fonts and Colors -> Identifier. This will unfortunately change all class names, methods names, and variable names. You cannot change the attribute color without on its own. Please see Visual Studios for a full list of how the items relate to color changes.