Seconded. I've been working on a webapp that's meant to work on iOS and I haven't figured out any way to debug it from my Linux machine, even with my phone being jailbroken.
Side note, if you just want to test with WebKit: GNOME Web (sudo apt install epiphany) uses WebKit internally. It doesn't have a responsive design mode or even a way to change the user agent, but it does have the exact same rendering and JS engine.