How to let sites use pop-up windows in Safari in macOS Monterey

Not all pop-up windows are evil spam, some of them remain genuinely useful. Here's how to get Safari on macOS Monterey to show you the ones you actually want, while still shielding you from all of the rest.
Safari for MacSafari for Mac
It is still the case that there are websites that use pop-up windows like it was the early 2000s and we hadn't really heard of spam. Safari on macOS Monterey will protect you from them, and protect you so well that you almost certainly don't even notice.