WKWebView != Safari.  Safari is built on top of WKWebView.  Likewise, Firefox is build on top of WKWebView.  Firefox is not built on top of Safari, so your Safari skin statement is incorrect.  Its called mobile app development, you work with the APIs provided to you by the OS.  Attempting to write your own low level networking and rendering libraries that bypass those provided by OS will simply mean your app is not released on the app store.  Should Mozilla not release a browser on mobile cause as its not &#x27;true&#x27; to your definition?