They've made a prototype for that: https://www.inkandswitch.com/embark/
Sadly not released.
A couple reasons we've decided not to share the demo widely: 1) it's research software, not developed to the quality standards of a commercial product, so we don't want people to get confused or disappointed by that, 2) the prototype heavily uses the paid Google Maps API.
We've also publicly released demos of some related work, like Potluck, an interactive medium built on text notes:
Blog post: https://jakelazaroff.com/words/a-local-first-case-study/