You can look at files like these to recover/transfer specific data. *bookmarks and history: places.sqlite *bookmark backups: JSON backups in the bookmarkbackups folder *SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data) *logins.json and key3.db (decryption key) for Passwords saved in the Password Manager *cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager *persdict.dat for words you added to the spelling checker dictionary *permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences *sessionstore.js for open tabs and pinned tabs and tab groups *http://kb.mozillazine.org/Profile_folder_-_Firefox *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox