URLs
Behind the single front door, every service still needs an address — a name a person or another service can reach it by. URLs is the scheme that assigns those names: which domain a service answers on, how its hostname is formed, and why. The point is predictability — a service’s address should follow from what it is and who it’s for, not be improvised per deployment.
The naming carries meaning, too. Distinct domains can separate distinct worlds — the real-identity workplace from the volunteer commons — so an address says something about which side of the enclave it belongs to before you ever reach it. The front door that terminates and routes these names is Edge; what each hostname points to, and the logic behind it, is the scheme described here.