Go to the "Processes" page (Processes in left panel) - The "Export Maps" is accessed from the three dots in a vertical line (in right panel of the maps page), to the right of the red “soft delete map”. You will only see this option if you are a Map Manager or Owner. If you are not, click on the SHARE tab in the right panel and you will see who is. They can do this or grant you the rights to do so.
The export is a basic structure. It exports a standard JSON format file of the map which we are using for transferring Elements maps into other formats (like MS Visio), so that you can take content into other formats or tools. Though not as useful or functionally rich as using in Elements, it is a complete record of the content you are holding online with us, in a format you can edit and import into other applications in the future, should you ever want to.
Through the APIs, it would also allow anyone to create an import from the standard JSON format into a tool or format of their choosing.
There is a basic utility which is open source for importing JSON format exports into Visio. If you would like access to this please contact email@example.com