Huh. That seems not super important to me. Presumably he could make a option/version where the icon didn't change?
Yeah, seems like a lame excuse to permissions grab crazy privilege.
You should have read a few more lines of that source - it also sends an "active" message to the tab, which is what adds and removes the copy/cut/paste event handlers.
You need to detect and stop sound. You swap out active memory.
What does any of that have to do with making sure input fields are pasteable?