From the post Add launch at login setting to a macOS app, I learned how a macOS app can add a menu item to the right side of the menu bar. These items are officially referred to as menu extras. Informally, apps that use this feature are often referred to as Menu Bar Apps.

Apple provides excellent documentation on the menu bar, including its structure and design principles, in The Menu Bar. This reminded me that I haven’t revisited the Human Interface Guidelines in quite some time.