I've never had a "What's new" tab ever open because I disable the customized home page where that's displayed. I'm guessing you're not aware that's an option.
Please show me where in either of those documents it explains it's going to download a 4GB model.
I use an extension that gives me a customized homepage, but I still always get the "what's new" tab on every major version upgrade.
It's a totally separate tab that opens. It's got nothing to do with what you use as your homepage.