I enjoyed using this add-on on Fennec (the old version of Firefox for Android). However, as of now, it does not work on Fenix (the new version of Firefox for Android).

[ FYI: We can now install any add-ons on the Nightly distribution of Fenix - see: https://blog.mozilla.org/addons/2020/09/29/expanded-extension-support-in-firefox-for-android-nightly/ ]