Shoji

Shoji is a privacy screen for your Mac. Press Command-L and a soft screen slides shut over everything on every display; Touch ID slides it open again with every window exactly where you left it. Focus Blur keeps only the window you are using sharp, so you can work in a cafe, on a plane or in a shared room without people reading over your shoulder. You can blur one app, everything but the window in use, or the whole Mac. Shoji needs no macOS permissions, no account and has no analytics. $14 once, with a free 24-hour trial.