if you have lots bookmarks, and if you want to edit them in a text editor, here's how.
Here's why you might need to do this. I have 7 local links as bookmark. Today i moved the dir. So, i need to update all links in the bookmark. If you use the Firefox GUI to edit (【Ctrl+⇧ Shift+o】 or menu 〖Bookmarks ▸ show All Bookmarks〗), it's gonna be one by one, tedious. I rather use a find/replace operation.
The Firefox bookmark is at 〔~/.mozilla/firefox/wix458pt.default/bookmarkbackups/〕
It's a JSON file. Open that, edit it, save.
Now, goto Firefox, open the bookmark manager 【Ctrl+⇧ Shift+o】, then menu 〖Import and Backup ▸ Restore ▸ Choose File…〗, then select the file you just edited. To show hidden file, press 【Ctrl+h】.