SDK which is a core part of ONLYOFFICE Desktop Editors.
Official website: http://www.onlyoffice.com/apps.aspx
Code repository: https://github.com/ONLYOFFICE/desktop-sdk
If you have any problems with or questions about ONLYOFFICE Desktop Editors, please visit our official forum to find answers to your questions: forum.onlyoffice.com or you can ask and answer ONLYOFFICE development questions on Stack Overflow.