Vimperator https://addons.mozilla.org/en-US/firefox/addon/vimperator/
to
Vimium-FF https://addons.mozilla.org/en-US/firefox/addon/vimium-ff/ or Saka Key https://addons.mozilla.org/en-US/firefox/addon/saka-key/
–
Session Manager https://addons.mozilla.org/en-US/firefox/addon/session-manager/
to
Tab Session Manager https://addons.mozilla.org/en-US/firefox/addon/tab-session-manager/