It was such an iconic machine. Ironically, at the time I hated them. (I probably still wouldn't want to use one even now, but now I only have to look at pictures of them, and they admittedly are nice to look at.)
I had a friend in high school whose family had one of these in their living room, and it was running OS 9. It was practically useless, but I forget what he did on it. I seem to remember that it ran World of Warcraft, but now I'm questioning my memory if that was really possible or not.
His family also got the first iMac running OS X, and that was such a beauty to behold. I mean, maybe the design wasn't as colorful or iconic as the G4 generation, but man that OS was sweet.
You could upgrade to OS X on the colorful ones, I installed 10.0 on release day and got an OS X tee shirt and wore it to school because what was I thinking. It was fun times. I remember having to open Emacs to make some system change to better support IRC in Ircle and I had no idea what I was doing but it was Unixy!
It did. I checked their opensource repo and it looks like they removed it in 10.15. The shell was also tcsh at the time and the terminal, I think, defaulted to black on white. Everything about it was unfamiliar to a Mac user, it felt like an old library Dynix system.