* Press ⌥ while hovering over the green circle. The icon changes to a + sign and clicking it uses the maximise behaviour.
* Double-clicking the title bar.
* From the menubar: Window > Zoom.
Double-clicking the title bar, a typical Apple feature that is totally undiscoverable except by stumbling upon it or having someone show you.
https://support.apple.com/en-gb/guide/mac-help/mchlp2469/mac
In addition, macOS and iOS come with a “Tips” app (yellow with a lightbulb icon) which covers several topics.
What they’ve done with the CMD-? keyboard shortcut that nobody knows about has to be the most brilliant UI that nobody uses.
* Press ⌥ while hovering over the green circle. The icon changes to a + sign and clicking it uses the maximise behaviour.
* Double-clicking the title bar.
* From the menubar: Window > Zoom.