Apple allows only a single browser engine on their iOS devices, which is Safari's webkit. All other browsers on iOS, despite their names, are forced to use this

Apple allows only a single browser engine on their iOS devices, which is Safari's webkit. All other browsers on iOS, despite their names, are forced to use this engine instead of their own browser engines. Since Apple doesn't prioritize web, the development of webkit typically lags behind other browser engines, such as Chrome's Blink, or Firefox's Gecko. Plus, there are important bugs that Apple doesn't hurry to fix. Keep this in mind if you care about web on your mobile device.