To export a page or stack as a Markdown file, do the following:
Access the menu for the page or stack. If the page or stack is in the sidebar, hover over the item and click on the three-dot menu icon. If the page or stack is open in the work area of the workspace, you can click on the three-dot menu icon located at the top-right of the open page or stack.
Click on the “Export as Markdown file” option. (This will start the export/download process.)
The export/download process may take a few minutes depending on the size of the page or stack.