Firefox has two different browsers one for IPAD based on Webkit and the other one for IPHONE based on Gecko (thanks to UE DMA rules)
https://www.macrumors.com/2024/01/26/mozilla-on-apple-eu-browser-engine-change/#:~:text=iPad Air-,Mozilla is 'Extremely Disappointed' With Implementation of,Apple's EU Browser Engine Change&text=In iOS 17.4%2C Apple is,Act in the European Union.