Board Thread:Support Requests - Designing Your Wiki/@comment-34288720-20190327171231/@comment-168424-20190327180825

That's not an infobox.

It's a fancy unordered list styled with CSS.

You need to look at the templates (Template:Mainpage Connect, Template:Mainpage Staff) and CSS (MediaWiki:Mainpage.css) and figure out how it works.