Well, so much for me having the right side of history 🙂

Thanks for the correction! I had a proper look at the CUPS page on Wikipedia and it's as you say:

Michael Sweet, who owned Easy Software Products, started developing CUPS in 1997 and the first public betas appeared in 1999.[5][6] The original design of CUPS used the Line Printer Daemon protocol (LPD), but due to limitations in LPD and vendor incompatibilities, the Internet Printing Protocol (IPP) was chosen instead. CUPS was initially called "The Common UNIX Printing System". This name was shortened to just "CUPS" beginning with CUPS 1.4 due to legal concerns with the UNIX trademark.[7] CUPS was quickly adopted as the default printing system for most Linux distributions. In March 2002, Apple Inc. adopted CUPS as the printing system for Mac OS X 10.2.[8] In February 2007, Apple Inc. hired chief developer Michael Sweet and purchased the CUPS source code.[9] On December 20, 2019, Michael Sweet announced on his blog that he had left Apple.[10][11] In 2020, the OpenPrinting organization forked the project, with Michael Sweet continuing work on it.[12][13]

This is kind of counter to the point I was making, so thanks for bringing it up. Apple still released some of their software under a free license back then, but without CUPS, it's nowhere near as significant. I guess it's worth mentioning that Apple forked KHTML from KDE as Webkit and continues to develop and maintain that browser engine today. However, Safari is not free software. Webkit is free software because KHTML was released under the LGPL, which prevents derivative software from developing it under a proprietary license.

Although, Apple's own contributions and "any further contributions" are available under the BSD 2-Clause license: https://webkit.org/licensing-webkit/

Which kind of contradicts what I've read on the Wikipedia page where it says certain parts of the browser are licensed under LGPL and others are licensed under the BSD license...

I have no idea how it ended up that way, but there's this announcement: https://docs.webkit.org/Other/Licensing.html