Safari

Safari is a web browser developed by Apple, based on the WebKit rendering engine and JavaScriptCore scripting runtime. It has been included with macOS since 10.3 Panther, replacing Internet Explorer for Mac as the default web browser, and with iOS since its initial release.

While Safari is an operating system component, on macOS, it can be updated independently of the core operating system. Typically, a major Safari version branch will continue to support the previous two releases of macOS, with these updates distributed via Software Update.

Safari Technology Preview
Safari Technology Preview is a version of Safari that is regularly updated with recent WebKit development work. It is similar to Google Chrome Dev and Firefox Developer Edition, in that a release is made every few weeks, allowing web developers to test new changes before they are released to the public, whether through Safari or other browsers. While the previews are typically stable, they are still not intended for general use.

WebKit
The WebKit project is the browser engine creating the core of Safari. Beginning as a fork of the KHTML project, WebKit was intended as a competitor to the then-popular Microsoft Internet Explorer Tasman (Mac) and Trident (Windows) engines, in addition to Mozilla, the successor to Netscape and predecessor to Firefox.

It is comprised of the following major components:


 * WebKit: High-level web browser components that can be embedded in an app with ease.
 * WebCore: Low-level rendering engine implementation that can be used to more closely customise WebKit behavior, forked from KHTML.
 * JavaScriptCore: The JavaScript engine implementation, forked from KJS.

WebKit components have been heavily used by parties other than Apple:


 * Google Chrome: Initial versions of Chrome were based on WebKit, paired with the Google-developed V8 JavaScript engine. Chrome forked WebKit in 2013 to create Blink.
 * Android: Until version 4.4, Android bundled a copy of WebKit for use by the Browser app, and by apps that require embedded web browser functionality. As of 4.4, Android requires an external browser app such as Chrome to be installed, which is also used as the system-wide web rendering engine.
 * Nokia mobile operating systems Symbian S60, Maemo, and MeeGo, and MeeGo successor Sailfish OS
 * BlackBerry OS 6.0 and later
 * Adobe AIR
 * Amazon Kindle
 * Nintendo 3DS
 * PlayStation 3
 * Tizen
 * webOS

While Safari is no longer released for Windows, WebKit continues to fully support Windows.