Roboto has a dual nature. It has a mechanical skeleton and the forms are
largely geometric. At the same time, the font features friendly and open
curves. While some grotesks distort their letterforms to force a rigid
rhythm, Roboto doesn't compromise, allowing letters to be settled into
their natural width. This makes for a more natural reading rhythm more
commonly found in humanist and serif types.

This is the Roboto Slab family, which can be used alongside the normal
Roboto family and the Roboto Condensed family.