var microsoft = microsoft
Updates that don't require a restart will install right away but ones that do won't restart your computer without your permission.
(Updates for your Windows Store apps are handled in the Store.
Open does not impact security related patches and is not available in Windows 10 Home.
screen is for: Give me updates for other Microsoft products when I update Windows: This is pretty self-explanatory.
I recommend checking this option so other Microsoft programs you have installed will get automatic updates too, like Microsoft Office.