At the moment it's pretty unclear what tools & technology are being made available, to alliance mbers, & the piblic. They have a couple brief repos on gothub, including- no shocker- specs for a RADIUS extension. But seemingly very little software available publicly on github.
I hope eventually this sort of tech comes down to being something that, for example, openwrt'ers might be able to setup.at BattleMesh, or something hackspaces can configure their local meshes to support. Perhaps folks on chaosvpn or dn42 or others could likewise join their wifi systems via these tools and technologies.
Atm the faq lists WBA OpenRoaming as a specific internetwork, a set of standards, amd some tooling. Hoping we see this really open up & flourish. Currently the tooling feels not accessible/open, but definitely reserving judgement & very interested & hopeful.