diff --git a/endpoint_search.go b/endpoint_search.go
index 7c80dea..4988f10 100644
--- a/endpoint_search.go
+++ b/endpoint_search.go
@@ -11,6 +11,8 @@
 )
 
 // Availability describes the accessibility of a specific service endpoint.
+// Identity v2 lists these as different kinds of URLs ("adminURL", "internalURL", and "publicURL"), while
+// v3 lists them as "Interfaces".
 type Availability string
 
 const (