I'm curious what does all this WIndows/Android/IOS/Linix/Mac/WIndowsStore/SamsungTV/Tizen/WebGL Support stuff means? What does it actually do? I mean obviously support, but it wasn't on any Unity installation before. Reason I wonder because it's a lot of download storage that I don't want to download unless it's needed absolutely. I have script reference and documentation online, so what's the difference?
It means you won't be able to build for specified platform unless you include them in your installation options.