Cantarell is available as a variable Opentype font. Source releases are available on gitlab.
Cantarell was originally designed by Dave Crossland as part of his coursework for the MA Typeface Design program at the Department of Typography in the University of Reading, England.
After the GNOME project adopted the typeface in November 2010, minor modifications and slight expansions were made to it over the years. Pooja Saxena initially worked on the typeface as a participant of the GNOME outreach program and later developed her own Devanagari typeface Cambay, which included a redesigned latin version of Cantarell. It was backported to the GNOME branch of Cantarell by Nikolaus Waxweiler, who also performed other janitorial tasks on it.
Given the decaying state of FontForge (arcane user interface, heaps of quirky and buggy behavior) and the very early development status of alternatives such as TruFont, Nikolaus Waxweiler started redrawing Cantarell in the proprietary and Mac-only Glyphs.app under mentorship from Jacques Le Bailly ("Baron von Fonthausen"). Later, Alexei Vanyashin and Eben Sorkin reviewed the design.
Frequently Asked Questions
What is the relation to Cantarell on Google Fonts and why isn't that updated?
Google requires an explicit oblique/italic variant, which we currently lack.
Why only variable?
Cantarell only distributes a variable font since version 0.303. GNOME historically bets on technologies that makes complex things easier. Specifically it avoids deployment conflicts.
Why does Cantarell not support my language/missing a specific glyph?
Take a look at the current list of known issues and file a request if yours is missing. Do note that Cantarell is currently not under active development.