Looks like he used swingjs[0] to port the applets to javascript since it hasn't been possible to run Java applets in a Chrome since v45 circa 2015. Always nice to see web 1 code live on.
Was hoping someone would comment on that -- he said it so casually, like he just had to the add the "-script"! So glad that you closed the loop. I was looking at what it would look like to setup an AI pipeline to port them to modern responsive typescript + three.js code, but now that I look, it appears that these aren't open source...?
I loaded one of the pages up for fun expecting an error message. My mind was blown when I saw a loading screen and then the applet load. Pretty awesome. I've got to try swingjs with some applets I wrote decades ago.