This doesn't install at all, the button "Add to Firefox" is greyed out and it provides another yellow button instructing "To find add-ons compatible with Firefox for Android, click here". Since when is Adblock Plus for Firefox for Android not compatible with Firefox for Android anymore? There are only 15 extensions found to be compatible with Firefox for Android anymore and here they are:
AdGuard AdBlocker (no good)
NoScript Security Suite (what the hell?)
LeechBlock NG (well it says "NG" = no good)
YouTube High Definition (no thanks)
uBlock Origin (what the hell?)
Ghostery - Privacy Ad Blocker (what the hell?)
Search by Image (gimme a break!)
BitWarden - Free Password Manager (software to steal your identity)
Tomato Clock (garbage)
Decentraleyes (garbage)
Privacy Badger (no thanks)
Web Archives (no thanks)
Video Background Play Fix (umm, I give up)
Google Search Fixer (fuck off!)
Dark Reader (nobody can read in the dark)

It's hopeless, I will have to hack the system somehow to install AdBlock Plus. Some moles got into Mozilla and destroyed the system?