Headers and navigation repeat identically on every page — mouse users skim past them in an instant, but keyboard users tabbing one stop at a time have to press Tab dozens of times just to reach the content. A skip link sits first in the tab order, hidden off-screen with the `.sr-only` technique (see visually-hidden) until it receives focus, at which point it becomes visible.
Pressing Enter follows an anchor like `href="#main"` and moves both focus and scroll straight to the content. It's easy to forget that the target needs `tabindex="-1"` so it can actually receive programmatic focus.
The demo starts at the top of the page: pressing Tab reveals the hidden skip link, then pressing Enter jumps focus past the navigation straight to the main heading.
When to use
Add one by default to any page with 5+ nav items or a repeated header/sidebar layout. Lower priority on a single-page landing site.