One of the things that confused me about the attributes used to decorate a Visual Studio were the hardcoded guids in the examples. I didn't know where they came from or what I could use. In fact, I had the impression I had to generate my own guid for each definition like how you need to assign one for an editor factory.

It turns out that these are defined guids that you must use for certain activities. They're defined in Microsoft.VisualStudio.VSConstants as static readonly. Like String.Empty, this means you can't use them in an attribute decoration and is why you see string literals instead. Since I couldn't find a list of the actual guids, and I needed them, I wrote a quick console app to retrieve them from the VSConstants class. I then placed them in constant, string form in my own class. Here they are in case you need them as well.