This page renders the canonical white header (.navbar-default) at full browser width so you can see every element — the logo, the menu items, the icon buttons, the search field and the user menu — without the responsive script collapsing anything. Narrow the browser window to watch the responsive behaviour: the user menu collapses to an icon first, then the search field shortens, and finally the menu items move into the overflow (“more”) menu.
The same header markup is shown, constrained to the documentation column, in the Menu link and Accessibility examples on the Header documentation page.