This feature allows a user to click on any URL/link on any app and the page will open on the last active profile regardless of which one is set to "default." This is to ensure that there's no need for any third party apps to define which URL gets opened on which profile.
When I am in work mode any external/url i click on from any app will open in my work profile since that is the profile I am active in.
I then swipe over to my personal desktop where I have Discord and a personal profile of chrome. I click my personal chrome to check my personal gmail, then i switch over to discord where a friend send me a funny youtube video. i click that link and the video opens in my personal profile because that was the last active profile of chrome.
after i watch the video i swipe over to do my work again. i get a ping from a coworker on slack. i click that link and now that url opens on my work profile because that was now my last active profile.