Earlier quoted context omitted.
The tabs on the home page aren't wired up because doing so requires JavaScript > Tabs should be managed by adding custom javascript code. All you need is to add the [aria-selected=true] attribute to the active tab.
I have a vague feeling that tabs should be doable in pure CSS/HTML, but I might be thinking of menus (where the menu is a sub element of the button and thus visibility can depend on mouse position)
one can do one level of tabs using # fragments and :target selector if I recall correctly