Are Xennials/Xellenials an American generation sub class? Or is this an international phenomenon?

Definitely international, and we can all relate to coming of age in a newly digital world. But with differences. Here in Britain, a lot of the 80s TV shows Americans here love and gush over either never came or didn't do anything ( maybe thrown on satellite channels as filler). References to, say, Macguyver, in other shows went over our heads. For rock/alternative music, there was a big divide in our scenes between I'd say 1994 (Kurt Cobain's death) and 2001 (the rise of The Strokes) with little real crossover from either side. Shame, as I've found a lot to like in US alternative. Rap was only really popular here in diverse cities until Eminem. For gaming, we were very much Sega Land between the home computers and Playstation, with the Megadrive (Genesis) being bigger than the SNES. The NES didn't do much while the Master System was decently successful as a budget console (though with the poor kid stigma). Sonic's a bigger deal than Mario here. The Gameboy was universal, we loved it as much as you and no other handheld could compete. At least in the 80s, cartoons and kids shows were often at least a year later for us. We didn't get the Ninja Turtles (or Hero Turtles officially for us thanks to ridiculous censorship rules at the time) until about 1989.