For most browsers. unless you are using one of teh "Back up to cloud" programs the passwords are encrypted and will not transfer to a new system.
For Chrome. it backs up to the "Cloud" as does Firefox.. when it works.
On my Chrome books I can do a "power wash" (Blow 'em back to "Out of the box" and in minutes it's all back and running.. Or I can (And have) taken a new one out of the box and .. Before my Windows 10 machine asked for my PIN to log in to Windows (not even connected to the net yet) the Chrome book was back in operation with about half the stuff imported including the password file and bookmarks.. Took a few minutes for all the extensions to download.
