How can I create an extension for another extension?

Question

JavaScript

There is an extension. It starts at the right time and opens its window separately from Google. In this window there is a button "confirm". How can I track (in my extension) the opening of the window of the first extension and click on the confirm button with the code?
PS: In the open window of the first extension html markup. In fact, this Google window opens

Answer 1

Inside the background page, set the handler:

chrome.tabs.onCreated.addListener(function(tab) {
    console.dir(tab);
});

It will fire every time you open a new tab, so nothing prevents you from keeping track of all the tabs you open in this way.