I'm now using cVim[0] plugin on Chromium. When I've switched from Firefox a year ago there was no real alternative to keysnail[1]. Backwards compatibility between Firefox releases began to break beginning of 2017. mooz, the developer of keysnail, managed to do some heroics and bring back the usability of the plugin on the never versions. Finally, Firefox 57 put the nail in the coffin and keysnail was declared dead on the spot. I've tried some alternatives for a few weeks but none could deliver. I found cVim on Chromium, and that saved the day.
See what fellytone84 had to say about keysnail, here on HN, 4 years ago [2]:
I consider Mooz's Keysnail Firefox add-on to be the most impressive keyboard oriented browsing tool. It's endlessly configurable, dotfiles in javascript--really nice to work with.For Chrome, the Vimium extension is very good, but recently I've been having a lot of fun with a similar, more configurable alternative called chromium-vim.
It looks like someone got cVim mostly working on firefox in a day, but never had time/motivation to do a real port.
So while I do miss the old extensions, and disagree strongly with how they went about it, any particular thing that's available only on chrome isn't really because chrome is better. With a little push cVim could support both browsers.
Since Firefox has similar extension interface with Chromium, any Chromium extensions should be able to work with Firefox with (relatively) small amount of works. In fact, cVim seem to be mostly works in Firefox according to its author here: https://github.com/1995eaton/chromium-vim/issues/520
Mooz has made xkeysnail which can do some of the same things, anywhere in X.
There's also a menagerie of Vimperator alikes for Firefox: Tridactyl, Vim Vixen, Surfingkeys, Vimium-FF, VVVimpulation. Most of them have improved substantially since September 2017.
Yes, I know. I'm using xkeysnail on Linux for C-n, C-p and C-m keybindings which I haven't seem to make it work in cVim. And for Windows, AHK for the same functionality.
The new versions of Firefox have almost the same plugin interface as Chromium. If you're satisfied with it, then why aren't you satisfied with it?