said by amazingm:The bookmarks are stored in the file: places.sqlite located in the user AppData Mozilla folder. In addition, Firefox automatically saves the current bookmarks daily in the bookmarkbackups folder....
I have manually manipulated these files before (backed-up/restored/transferred to other profiles or installations)
The procedure works.
Also, if you keep a lot of tabs open, it is worthwhile to manually backup the
sessionstore.js (or .json) file to elsewhere.
Any of the above-mentioned files can be manually backed up even while the browser is running, but can only be manually restored when it is not.