This works on other system menu bar icons, as well as on menus in some apps. For example, holding option down with the File menu open in most Apple apps gets you the "save as" item.
Now you'll spend your next hour option-clicking random stuff. Sorry.
Option is the most irritating feature of mac UX, everywhere it keeps popping new hidden features, it is true even for top menu and simple navigations.
Most irritating for me is if all windows of an app are hidden (minimized), simple Cmd+Tab doesn't brings anything to focus, but some gymnastics with Option and voila now you can see your Slack.
Author here! Yeah, that menu option was super useful to find, too. I've not really used this shell script for a while (I spend a lot less time in coffee shops now because Covid) but I still use the option-click thing regularly.
Now you'll spend your next hour option-clicking random stuff. Sorry.