https://www.benjaminoakes.com/programming/2021/04/23/Use-Vim-Emacs-or-Sublime-Text-key-bindings-in-Firefox-Developer-Tools/
Use Vim, Emacs, or Sublime Text key bindings in Firefox Developer Tools | Benjamin Oakes
Apr 23, 2021 - In the Editor Preferences section of the developer tools settings, you can choose to use Vim, Emacs, or Sublime Text key bindings instead.
firefox developer toolssublime textkey bindingsusevim