Among Microsoft software development tools, DTE80 is the Microsoft Development Environment 8.0 Extensibility namespace. EnvDTE80 contains the objects and members for Visual Studio core automation, possibly called from an app. It extends and compliments the functionality provided by EnvDTE. It is used by macros and extensions, written in C# or VBA, to automate Microsoft Visual Studio.
References
DTE80 Wikipedia(Text) CC BY-SA