cantarell-fonts (The Cantarell typeface family)

The Cantarell typeface family  is a contemporary Humanist sans serif,
and is used by the GNOME project for its user interface and the
Fedora project.)

Cantarell was originally designed by Dave Crossland as part of his
coursework for the MA Typeface Design programme at the Department
of Typography in the University of Reading, England.

This is the open font officially chosen by default for the GNOME 3
and for Fedora branding materials.