Class Libraries & REST APIs for the developers to manipulate & process Files from Word, EXcel, PowerPoint, Visio, PDF, CAD & several other categories in Web, Desktop or Mobile apps. Develop & deploy on Windows, LinuX, MacOS & Android platforms....provided by Gmail and described as X-GM-EXT-1 . We have added a GetMessageThreads...Gets information whether Gmail X-GM-EXT-1 extension is supported...