Google maps is drunk. I'm at the blue dot & wanted to see how long it would take to walk to the red flag and this is the route it suggested.
(lemmy.dbzer0.com)
The project is open source: https://codeberg.org/cartes
They combine a bunch of different services and list them all out here (unless you speak french, you'll want to translate the page): https://cartes.app/verso
Looks like they're using Valhalla for routing as well as MOTIS/Transitious, Node-GTFS, GRAZE, and Transport.data.