If your still watching the thread. Bookmarks.html just copies the bookmarks. If you also want to copy your passwords & cookies etc., so firefox works exactly as it did in the old distro, copy all 4 of these files.
I've been doing this every time I set up a new computer and it works flawlessly. I got tired of having to look up passwords when revisiting old web sites. So a while back I did a little investigating, and discovered these files.
Just make sure firefox/iceweasel is closed when doing the copying or else the newly copied files will be overwritten.