The mobile version of Firefox for iOS/iPadOS is not using the same Gecko engine as Android Firefox and (desktop) Firefox does as you can thank Apple's restrictions on what browser engine can be used on iOS/iPadOS. https://support.mozilla.org/en-US/kb/add-ons-firefox-ios Extensions at https://addons.mozilla.org are only available for Android Firefox and desktop Firefox (for Windows, macOS, and Linux). Firefox for desktop https://addons.mozilla.org/firefox Firefox for Android https://addons.mozilla.org/android/