Bookmarks - How to export the FireFox bookmarks
This article explains how to export your bookmarks to an HTML file, which can be used as a backup or for importing into another web browser.
Click the Library button on the toolbar.
Click Bookmarks.
Click Show All Bookmarks.
Click the Import and backup your bookmark icon, then click Export Bookmarks to HTML...
Select the location from your OneDrive to export the files to, then click Save.
Your bookmarks are now back up and ready to move to another browser or restore later to a new device.