diff --git a/go/delivery/composed.go b/go/delivery/composed.go
index a77b6ee..d22151a 100644
--- a/go/delivery/composed.go
+++ b/go/delivery/composed.go
@@ -141,14 +141,19 @@ func checkDigest(digest, of string) error {
 // own choice (`upgrade` with policy) included. Rewritten when the policy changes. Empty on a composition made by hand
 // (mesh-compose), whose want the operator writes.
 type ComposedDigest struct {
-	V          int       `json:"v"`
-	Digest     string    `json:"digest"`
-	Judgement  Judgement `json:"judgement"`
-	Against    string    `json:"against,omitempty"`
-	Words      string    `json:"words,omitempty"`
-	Policy     string    `json:"policy,omitempty"`
-	PolicyFrom string    `json:"policy-from,omitempty"`
-	PolicyWhy  string    `json:"policy-why,omitempty"`
+	V         int       `json:"v"`
+	Digest    string    `json:"digest"`
+	Judgement Judgement `json:"judgement"`
+	Against   string    `json:"against,omitempty"`
+	Words     string    `json:"words,omitempty"`
+	// UserListOnly says the composition differs from the one the node's have names only in the bus's user list (the
+	// bus module's file `<module>.bus-users`), whatever the judgement says of its mount: the assigner writes such a
+	// revision into the bus node's want at once, outside the record hold, at the fingerprint the node runs (ADR 0539
+	// clause 7).
+	UserListOnly bool   `json:"user-list-only,omitempty"`
+	Policy       string `json:"policy,omitempty"`
+	PolicyFrom   string `json:"policy-from,omitempty"`
+	PolicyWhy    string `json:"policy-why,omitempty"`
 }
 
 // The upgrade policies and their sources a composition's value names: catalogue.PolicyRoll, PolicyTogether and
diff --git a/go/delivery/composed_keys_test.go b/go/delivery/composed_keys_test.go
index bd3630e..fc03a5e 100644
--- a/go/delivery/composed_keys_test.go
+++ b/go/delivery/composed_keys_test.go
@@ -82,6 +82,7 @@ func TestComposedDigestValue(t *testing.T) {
 		{Digest: digest, Judgement: JudgedCannot, Words: "the composition the node runs is gone"},
 		{Digest: digest, Judgement: JudgedNeither, Policy: "record", PolicyFrom: "person", PolicyWhy: "the operator: its data"},
 		{Digest: digest, Judgement: JudgedNeither, Policy: "roll", PolicyFrom: "default"},
+		{Digest: digest, Judgement: JudgedNeither, Against: against, UserListOnly: true, Words: "only the bus's user list changes"},
 	} {
 		raw, err := EncodeComposedDigest(v)
 		if err != nil {