What the...? Pinafore, you're amazing!
I'm in ChromeOS rn, and, y'know, you can "appify" most windows by going to the top-right hamburger menu, selecting "Create Shortcut," and then, right-clicking on the new pinned shortcut in taskbar, choosing "Open as Window." (Until very recently, this process was just "Add to Shelf, but Google changed that, and ugh.)
BUT! When you're at pinafore.social, that same menu item is now called "Install Pinfore app"!! Whaaaaa?