Firefox history file
From Just Solve the File Format Problem
Firefox history files track the browsing history of a Firefox user, in the form of a database. The format has changed between versions.
Firefox 2
History files were kept in a Netscape/Mozilla database format called Mork, no longer used. It is text-based but not very human-readable.
Firefox 3
History files are kept in a SQLite database, places.sqlite, along with Firefox bookmarks. The format is documented in that article.
