Firefox config files

https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data (english)
https://support.mozilla.org/de/kb/wiederherstellen-wichtiger-daten-aus-altem-profil# (german)

# path:
  %APPDATA%\Mozilla → Firefox → Profiles → xxxxxxxx.default
# or
  %APPDATA%\Mozilla → Firefox → Profiles → xxxxxxxx.default-esr

# for backing it up and restore

# Bookmarks, Downloads and Browsing History:
  places.sqlite
  bookmarkbackups
  favicons.sqlite

# Passwords:
  key4.db
  logins.json

# Site-specific preferences:
  permissions.sqlite
  content-prefs.sqlite

# Search engines:
  search.json.mozlz4

# Personal dictionary:
  persdict.dat

# Autocomplete history:

# Extensions:
  extensions

# Security certificate settings:
  cert9.db

# Security device settings:
  pkcs11.txt

# Download actions:
  handlers.json

# Toolbar customization:
  xulstore.json

# User preferences:
  prefs.js