Home > Settings > Safari > Experimental Features, for Safari on iOS 14. Home > Settings > Developer, for anywhere in iOS 14 that uses the system HTTP library.

Home > Settings > Safari > Experimental Features, for Safari on iOS 14. Home > Settings > Developer, for anywhere in iOS 14 that uses the system HTTP library. Note that you'll need a device with development mode enabled for the latter. https://developer.apple.com/wwdc20/10111 https://developer.apple.com/wwdc20/10111 has more details near the end.