The Firefox version of Lazy Scholar is back: https://addons.mozilla.org/en-US/firefox/addon/lazy-scholar/
It will look and function similar to the Chrome version. Firefox is in the process of revamping their extension platform to support Chrome extensions, so if anything doesn’t work as expected, please contact me to let me know. I have labeled the extension “beta” because of this. You will need to be on Firefox version 53 (the latest non-beta version) or later for it to function correctly.