"Vintage" usually refers to actually old stuff, while "retro" refers to new stuff that looks/sounds/feels like old stuff. So GentleOS is a retro OS designed to run on vintage hardware.
(That distinction wasn't clear to me either, so I had to look it up - TIL).
That’s not true in computer terminology. “Retro” has a long history (“vintage” you might say haha) of referring to old hardware and software.
Just type the word “retro” into YouTube (for example) and you’ll see thousands of videos from hundreds of channels spanning decades talking about old games and computers.
(That distinction wasn't clear to me either, so I had to look it up - TIL).