Use of First Responder on Scene Dock

I know what the first responder is but have not found a practical use of the First Responder on the Scene Dock and in the Document Outline. It would be greatly appreciated if someone could shed some light on this.

Many thanks

It’s not very useful in iOS apps (but quite useful in macOS apps).

For example, you could make an view controller that has 3 text fields and a “Copy” button. Then connect that button to the “copy” action of the First Responder. Whenever you tap the button, it will take the text inside the active text field (whichever one that is) and puts it on the clipboard.

Many thanks, Matthijs! Very helpful for understanding its purpose and use.

Even with iOS app, I was able to test select all, copy, and paste. However, toggleitalic and toggleboldface, etc. don’t work. Good enough for now.