(But upon writing that I'm not sure where I got that impression from, and I can't find a citation for it right now, so treat the claim with skepticism.)
the Quartz compositor itself has "use[d] pdf internally"[2][3] ever since the initial launch of Mac OS X
> By the time OS X came out, these were less the kind of features that "the next great personal computer operating system" should have, and more the kind that they all had. What was new included how Quartz, the engine for OS X's "killer graphics," was based on PDF.
> "What does that mean?" asked Jobs. "You know when you go to the web and you see PDF documents? Well, that technology is now at the core of Mac OS X's graphics. So you can image PDFs instantly. So now all applications get this for free."
> It's how, to this day, every Mac app can produce a PDF document without needing a third-party app.[4]
[0]: https://web.archive.org/web/20100531072734/http://www.apple....
[1]: https://en.wikipedia.org/wiki/LaserWriter#Apple's_developmen...
[2]: https://www.youtube.com/watch?v=Ko4V3G4NqII / https://www.youtube.com/watch?v=6-fkYFV7rOY
[3]: https://en.wikipedia.org/wiki/Quartz_(graphics_layer)#Use_of...
[4]: https://appleinsider.com/articles/21/03/24/apple-launched-it...