Question: What descendant of KTHML was developed by Apple?

Context paragraphs:
KHTML: KHTML is a HTML layout engine developed by the KDE project.  It is the engine used by the Konqueror web browser.  Descendants of KHTML are used by some of the world's most widely used browsers, among them Google Chrome, Safari and Opera.  Distributed under the terms of the GNU Lesser General Public License, KHTML is free software.

Applesoft BASIC: Applesoft BASIC is a dialect of Microsoft BASIC, developed by Marc McDonald and Ric Weiland, supplied with the Apple II series of computers.  It supersedes Integer BASIC and is the BASIC in ROM in all Apple II series computers after the original Apple II model.  It is also referred to as FP BASIC (from "floating point") because of the Disk Operating System (DOS) command used to invoke it, instead of INT for Integer BASIC.  Applesoft BASIC was supplied by Microsoft and its name is derived from the names of both Apple and Microsoft.  Apple employees, including Randy Wigginton, adapted Microsoft's interpreter for the Apple II and added several features.  The first version of Applesoft was released in 1977 only on cassette tape and lacked proper support for high-resolution graphics.  Applesoft II, which was made available on cassette and disk and in the ROM of the Apple II Plus and subsequent models, was released in 1978.  It is this latter version, which has some syntax differences from the first as well as support for the Apple II high-resolution graphics modes, that most people mean by the term "Applesoft".

MacX: MacX is a display server implementation supporting the X11 display server protocol that ran on System 7, Mac OS 8, and Mac OS 9.  It also ran under A/UX.  Prior to X11R4 and the introduction of the PowerPC-based Power Macintosh, this server was developed internally by Apple Inc. for the Motorola 68000 based Macintoshes.  MacX was initially developed within the Networking and Communications organization as one component of the Apple DEC Alliance suite of products, but later was moved to Apple's A/UX group since X11 was (and is) an important part of UNIX user interfaces.  Versions supporting X11R4 and X11R5 were developed for Apple by a small team of engineers at AGE Logic, Inc., a San Diego, California company.  AGE also OEMed the MacX software under the trade name XoftWare for Macintosh.  Apple provided early versions of the Power Macintosh to AGE Logic, and the result was a binary that supported both the Power Macintosh as well as earlier, 68000-based systems.

Macintosh External Disk Drive: The Macintosh External Disk Drive is the original of a series of external 3.5" floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January 1984.  Later, Apple would unify their external drives to work cross-platform between the Macintosh and Apple II product lines, dropping the name "Macintosh" from the drives.  Though Apple had been producing external floppy disk drives prior to 1984, they were exclusively developed for the Apple II, III and Lisa computers using the industry standard 5.25" flexible disk format.  The Macintosh external drives were the first to widely introduce Sony's new 3.5" rigid disk standard commercially and throughout their product line.  Apple produced only one external 3.5" drive exclusively for use with the Apple II series called the "Apple UniDisk 3.5".

Apple Watch: Apple Watch (stylized as WATCH) is a line of smartwatches developed, designed, and marketed by Apple Inc. It incorporates fitness tracking and health-oriented capabilities with integration with iOS and other Apple products and services.  The original generation of the device was available in four variants: Apple Watch Sport, Apple Watch, Apple Watch Hermès, and Apple Watch Edition; each distinguished by different combinations of cases and first- or third-party interchangeable bands.  Apple Watch relies on a wirelessly connected iPhone to perform many of its default functions such as calling and texting.  It is compatible with the iPhone 5 or later models running iOS 8.2 or later, through the use of Wi-Fi or Bluetooth.  Announced by Apple CEO Tim Cook in September 2014, the device was released in April 24, 2015.  The Apple Watch quickly became the best-selling wearable device with the supply of 4.2 million smartwatches in the second quarter of the 2015 fiscal year.  The second generation of Apple Watch, released in September 2016, includes two tiers: Apple Watch Series 2 and Apple Watch Series 1, which includes the S1P chip, but is otherwise identical to the original.  The Series 3 was announced at a presentation at Apple Park on September 12, 2017 and was released on September 22, 2017.

Pink Pearl (apple): The 'Pink Pearl' apple is a purple-fleshed apple cultivar developed in 1944 by Albert Etter, a northern California breeder.  It is a seedling of 'Surprise', another pink-fleshed apple that is believed to be a descendant of "Malus niedzwetskyana".

Apple Lossless: Apple Lossless, also known as Apple Lossless Audio Codec (ALAC), or Apple Lossless Encoder (ALE), is an audio coding format, and its reference audio codec implementation, developed by Apple Inc. for lossless data compression of digital music.  After initially keeping it proprietary from its inception in 2004, in late 2011 Apple made the codec available open source and royalty-free.  Traditionally, Apple has referred to the codec as "Apple Lossless", though more recently they have begun to use the abbreviated term "ALAC" when referring to the codec.

MacOS version history: The history of macOS, Apple's current Mac operating system originally named Mac OS X until 2012 and then OS X until 2016, began with the company's project to replace its "classic" Mac OS.  That system, up to and including its final release Mac OS 9, was a direct descendant of the operating system Apple had used in its Macintosh computers since their introduction in 1984.  However, the current macOS is a Unix operating system built on technology that had been developed at NeXT from the 1980s until Apple purchased the company in early 1997.

Safari (web browser): Safari is a web browser developed by Apple based on the WebKit engine.  First released in 2003 with Mac OS X Panther, a mobile version has been included in iOS devices since the introduction of the iPhone in 2007.  It is the default browser on Apple devices.  A Windows version, now discontinued, was available from 2007 to 2012.

TvOS: tvOS is an operating system developed by Apple Inc. for the fourth-generation and later Apple TV digital media player.  tvOS was announced on September 9, 2015 at the Apple September 2015 event, alongside the 4th generation Apple TV.  On October 26, 2015, 4th generation Apple TV pre-orders began, and shipments began the following week.  At the Apple September 2015 Event, Hipster Whale's Andy Sum demoed "Crossy Road" for the Apple TV, available via the tvOS App Store.  Apple also announced that other apps (such as Netflix and HBO Now) would be coming to the Apple TV running tvOS.

Supporting paragraphs: KHTML Safari (web browser)
Answer: Safari