Nightly adds Microsoft Edge option to import wizard. Mozilla has started working on providing the users Edge data migration feature, you can see the result of their work in Firefox beta (probably this feature might not be available with Firefox 41, but is available for testing) and Nightly versions. In these versions, import wizard allows to bring Edge bookmarks and cookies into the Firefox browser.
READ: How to Import Chrome Bookmarks, Browsing History, Cookies and other data into Firefox
Importing Microsoft Edge bookmarks/ favorites into Firefox
As mentioned above, you need to be using either the latest beta or Nightly version on Windows 10.
1. Use Ctrl+Shift+B to open ‘Library’ window, click on ‘Import and Backup’, choose ‘Import Data from Another Browser’
2. In the import wizard, ‘Microsoft Edge’ (top option) is pre-selected by default, all you need to do is click ‘Next’ button, decide which items to import (cookies or favorites or both) and click Next, wait for import wizard to finish the task.
SEE: How to Export Chrome bookmarks to HTML file and import them later
3. It may take a while.
Imported items will appear in the library window, on the left sidebar under ‘Bookmarks menu’ as ‘From the Microsoft Edge’, you can see the same entry in the ‘show your bookmarks’ icon on the toolbar also.
New import options
Beta version offers the option to import data from Microsoft Edge, Microsoft Internet Explorer and Chrome browsers, where Nightly offers extra import option for another browser, which is Canary.