The File tab in the Diagram Viewer allows performing some basic file operations.
The corresponding window of the Online Diagram Viewer:

The corresponding window of the Desktop Diagram Viewer:

Using this tab, you can:
- download as (save the document in the selected format to the hard disk drive of your computer), save copy as (save a copy of the document in the selected format to the portal documents), print the file or rename it,
- view general information about the diagram,
- access the advanced settings of the editor,
- Help - open the built-in help center,
- Suggest a Feature - share your thoughts on improving ONLYOFFICE editors.