Hi, I don't use Waterfox, but maybe you can export to HTML from Firefox, then import from HTML using Waterfox: In Firefox, open bookmarks > Show All Bookmarks > Import and Backup > Export Bookmarks to HTML, and save them to somewhere convenient on your computer. Now open Waterfox and import from HTML.

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Waterfox is much the same as Firefox but watered down. The above should work with any browser.