It is explicitly plural where ‘you’ is hard to pull off as plural because it leans heavily towards singular, just like ‘they’ leans heavily towards plural. At least in the US afaik the main competitor is ‘you guys’ for plural, which is one of those terms that is normally meant as gender neutral but the words clearly are not. So despite being from a place where that is the correct way to say it I’m in favor of y’all becoming the standard across the whole language, which it seems like it might be moving towards doing.