This is only a widget without an attached app.
to use it simply look for it on your widget list (usually long pressing your launcher background)

Clean digital clock + date widget with a lot of customization abilities.

Source code:
https://github.com/y0av/MaterialClockWidget

READ_EXTERNAL_STORAGE is only there for fetching your current wallpaper for a nice preview in the configuration screen.

app icon made by monkik(https://www.flaticon.com/authors/monkik)