Apparently, the shell team at Microsoft threw in another keyboard shortcut to get focus to the tray notification area.  This is the section of the taskbar that contains the clock and various status icons.  For example, if updates are available on Windows Update, the Volume control (if enabled), and network status.

Press WIN+B to place keyboard focus on the first icon in the notification area.  If the “hide inactive icons“ feature is enabled, the first icon might be the left-facing cheveron ( < ) that toggles inactive icons into view.

Interestingly, when using WIN+B, no focus rectangle is shown.  Thus, it's difficult to tell where the focus is.  When using the Tab key to focus the taskbar, a small focus rectangle is shown around the selected icon.

One way to tell what has keyboard focus is to use the Context Menu key (or SHIFT+F10).

Also, when each icon gets focused, the tool tip associated with it appears.

WIN+B is undocumented in the standard Windows help.  Thanks to a poster on the Windows Off-Topic Tech mailing list for brining it to my attention.