macOS Tahoe enforces "squircle jail"—rounded-square app icons—on Mac App Store apps, but developers distributing outside the store can use the NSDockTilePlugIn API to display custom icons that persist after quitting. Iris is one example of an app offering alternative icons this way.
macOS Tahoe enforces "squircle jail"—rounded-square app icons—on Mac App Store apps, but developers distributing outside the store can use the NSDockTilePlugIn API to display custom icons that persist after quitting. Iris is one example of an app offering alternative icons this way.