One of the customization settings on iOS allows you to tint all of the icons/widgets on your home screen. Apps that don’t have the field specified for tinted just turn white on the Home Screen instead of showing any of the UI elements. You can see something similar happening to my Audible app, but the large white rectangle below is the Deezer widget when using the tinted setting.
https://forums.developer.apple.com/forums/thread/763246
