Firefox: How to import Bookmarks from another browser or HTML file
Before proceeding, you should make a backup of your current bookmarks.
Note: The imported bookmarks will be added to your existing bookmarks, which may result in duplicate bookmarks.
Click on the menu button to open the menu panel. Click Bookmarks and then click the Manage Bookmarks bar at the bottom.
- From the toolbar on the Library window, click Import and Backup and choose Import Bookmarks from HTML….
- Within the Import Bookmarks File window that opens, navigate to the bookmarks HTML file you are importing and select the file.
- Click the Open button. The Import Bookmarks File window will close.
- Close the Library window.
- The bookmarks in the selected HTML file will be added to your Firefox bookmarks within the Bookmarks Menu directory.
Original: https://support.mozilla.org/en-US/kb/import-bookmarks-html-file