It is not a terminal multiplexer feature, it is one of the terminal software itself.
I do not know if you read my initial commment, but MacOS Terminal (native app) has this feature. And it is not a terminal multiplexer like tmux or what you proposed.
I do not know if you read my initial commment, but MacOS Terminal (native app) has this feature. And it is not a terminal multiplexer like tmux or what you proposed.