Thanks. It's still not clear to me how MYCMesh users would be able to reach the internet.

They state in their FAQ they are not an ISP which leaves me to believe they don't buy transit from anyone.

But looking at that peering link there are only 122K prefixes being advertised at DE-CIX NY and NYCMesh only peering with 14 other ASes there.

That would leave large parts of the internet unreachable. Perhaps Hurricane Electric or one their other 14 peers at DE-CIX NY have agreed to be act as transit AS for NYCMesh?