Lesson I've long learned: never bookmark anything. Bookmarks are to temporarily remember a URL, not to archive content. If the content is important or meaningful to you, save the page.
[0] https://addons.mozilla.org/en-US/firefox/addon/single-file/
Naturally, you mean you'll SAVE that page, right? LOL.
Archiving even just a single webpage is non-trivial. You're dependent on the internet archive if you want a reliable backup.