diff --git a/03-DESIGN/01-to-be/39-milestones/bus-and-switch.md b/03-DESIGN/01-to-be/39-milestones/bus-and-switch.md
index 6b0d1e82..f863a31d 100644
--- a/03-DESIGN/01-to-be/39-milestones/bus-and-switch.md
+++ b/03-DESIGN/01-to-be/39-milestones/bus-and-switch.md
@@ -496,3 +496,7 @@ written; they are cited as "design 39 bus-and-switch B*n*".
   keys, the vault does not (P8).
 - **B24** (an equal generation in `licence-put`): with the same value it is unchanged; with a different value it is
   refused loudly as not newer (P3).
+- **B25** (the vault matching a token's secret name to a binding it learned at start): the `bindings` verb answers
+  `key` beside the §3 fields, as `binding.changed` does (B7); the vault's `licence-bindings` keeps `licence`, `key` and
+  `generation`, and compares the secret's key with the binding's key. One form travels; the vault never computes §10's
+  key form (P1, P7).