A choice between two views of one thing is now the same control everywhere: two halves in one frame, with the chosen half solid. Before, each area drew its own: a grey tray with a raised pill, a round pill pair, or two separate buttons. Nothing about what the choices do has changed.
One switch for a choice between two views
Visual or Code in Websites, Markdown or Formatted in the Notes editor, List or Board in Issues and Hiring, and Cards or List and Flow or Pages in Books now use one two-way switch.