These are optional IVsUserData properties that a language service can provide in order to influence the behavior of the text editor. You can get the IVsUserData interface by doing QueryInterface on the IVsLanguageInfo object of the language service implementation.
Assembly: Microsoft.VisualStudio.Shell.14.0 (in Microsoft.VisualStudio.Shell.14.0.dll)
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.