Earlier quoted context omitted.
It is complicated. Here is the story of two WebView implementations in iOS: Firefox is based on the WKWebView. Modern and Fast, but has a very poor (thin) API. It has zero options for interacting with the network stack, which is a requirement for content blocking. Bugs have been open since iOS 8, Apple does not seem to be interested or does not have the resources to surface more API. All the APIs are in WKWebView, ju…
Is either able to use JIT for JavaScript engine or is it only enabled for Apple's "blessed-process" iOS Safari?
For example, Firefox for iOS ranks exactly the same as Safari in speed benchmarks.