The notation is the mark: d∞, Archivo 800, tracking −.05em, light blue on the sides. No drawn die — the app is about any die, so the name does the work.
d∞
Lockups
d∞dInfinity
d∞dInfinity
d∞One colour
d∞dInfinityStacked
App icon and small sizes
d∞
Icon · ink
d∞
Icon · accent
d∞d∞d∞
32 / 22 / 15 px — tracking opens up at the smallest size