Open Data Commons Open Database License (ODbL) v1.0

The OpenStreetMap source snapshot and the adapted graph.json database are
distributed under the Open Data Commons Open Database License version 1.0.

Full license text:
https://opendatacommons.org/licenses/odbl/1-0/

You are free to share, create, and adapt the database provided that you
attribute OpenStreetMap contributors, keep the database open, and share
adapted databases under the same license. This notice is bundled for offline
use; the authoritative license is available at the URL above.