No, you can't get a list of windows opened by the page via window.open
(sadly). You'll have to keep track of them as you open them (assuming it's you who opens them).
If you were to do the more modern style of popup instead (positioned elements opened as virtual windows within the page), then of course you could readily get a list of them by doing a simple selector query (just add a class to them when they're showing, and then query the DOM for elements with that class).
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