This is an unofficial clock face for Fitbit OS bringing the swiss railway clock to your watch.
To build this app yourself, you have to own a Fitbit Ionic and visit this website: https://studio.fitbit.com/
To download the clockface directly follow this link on your smartphone: https://gam.fitbit.com/gallery/clock/c991aef0-8216-4e47-8f75-ee09cee61665