OutlookAddInDemo_cpp This project was seeded from https://code.msdn.microsoft.com/office/Outlook-2010-Building-a-C-0358a023 a sample project whose tutorial is at https://msdn.microsoft.com/en-us/library/office/ee941475%28v=office.14%29.aspx Microsoft flags it with the "Apache License, Version 2.0". The initial commit of the project files is thus under that license, by that owner.