diff --git a/modules/mesh-delivery-indexer/judge/judge.go b/modules/mesh-delivery-indexer/judge/judge.go
index 2d22f330..bd352368 100644
--- a/modules/mesh-delivery-indexer/judge/judge.go
+++ b/modules/mesh-delivery-indexer/judge/judge.go
@@ -95,6 +95,12 @@ func ShelfCounting(raws map[string][]byte, predefined catalogue.PredefinedList,
 // (novox/hq ADR 0578 §1, amended). The indexer judges so; the checker, which runs the judge built at the head of the change,
 // judges with Shelf.
 func ShelfWaiting(raws map[string][]byte, predefined catalogue.PredefinedList, longestMachine int, counts OldSectionCounts, known KnownPackages) (refused, waits map[string][]string, unnamed []string) {
+	return shelfWaiting(raws, predefined, longestMachine, counts, known, nil)
+}
+
+// shelfWaiting is ShelfWaiting where the seats the trunk case declares (A-337) are declared too, each where no module of the
+// shelf is its declarer's: a module the shelf holds declares by its own manifest.
+func shelfWaiting(raws map[string][]byte, predefined catalogue.PredefinedList, longestMachine int, counts OldSectionCounts, known KnownPackages, trunk trunkSeats) (refused, waits map[string][]string, unnamed []string) {
 	refused, waits = map[string][]string{}, map[string][]string{}
 	shelf := catalogue.Shelf{}
 	for name, raw := range raws {
@@ -117,20 +123,26 @@ func ShelfWaiting(raws map[string][]byte, predefined catalogue.PredefinedList, l
 		}
 		shelf[name] = m
 	}
-	between := Between(shelf, longestMachine, known)
+	also := trunkSeats{}
+	for seat, d := range trunk {
+		if _, held := shelf[d.module]; !held {
+			also[seat] = d
+		}
+	}
+	problems := between(shelf, longestMachine, known, also)
 	without := map[string]map[string]bool{} // by module: the problems between the rest, once asked
 	ends := func(module, problem string) bool {
 		if without[module] == nil {
 			rest := maps.Clone(shelf)
 			delete(rest, module)
 			without[module] = map[string]bool{}
-			for _, p := range Between(rest, longestMachine, known) {
+			for _, p := range between(rest, longestMachine, known, also) {
 				without[module][p] = true
 			}
 		}
 		return !without[module][problem]
 	}
-	for _, p := range between {
+	for _, p := range problems {
 		// The modules it names are asked first; only when none of them ends it is every module asked.
 		var of []string
 		for _, name := range Named(p, shelf) {
@@ -163,10 +175,15 @@ func ShelfWaiting(raws map[string][]byte, predefined catalogue.PredefinedList, l
 // the longest machine name (catalogue.DefaultLongestMachine when not above 0), DataProblems, and
 // PackagesCatalogueProblems against the known packages (nil judges no name).
 func Between(shelf catalogue.Shelf, longestMachine int, known KnownPackages) []string {
+	return between(shelf, longestMachine, known, nil)
+}
+
+// between is Between with the seats the trunk case declares outside the shelf declared too (A-337).
+func between(shelf catalogue.Shelf, longestMachine int, known KnownPackages, trunk trunkSeats) []string {
 	if longestMachine <= 0 {
 		longestMachine = catalogue.DefaultLongestMachine
 	}
-	between := CatalogueProblems(shelf)
+	between := catalogueProblems(shelf, trunk)
 	between = append(between, PackagesCatalogueProblems(shelf, known)...)
 	between = append(between, IdentityProblems(shelf, longestMachine)...)
 	between = append(between, DataProblems(shelf)...)
@@ -228,7 +245,7 @@ func Request(r composer.Request) (composer.Verdict, error) {
 	}
 	v := composer.Verdict{V: composer.Version, SDK: Identity()}
 	seen := map[string]bool{}
-	counts := trunkOldSections(r)
+	trunkCase := readTrunk(r)
 	known := knownOf(r.Packages)
 	for _, c := range r.Cases {
 		if seen[c.Name] {
@@ -242,7 +259,15 @@ func Request(r composer.Request) (composer.Verdict, error) {
 			}
 			raws[name] = m.Raw
 		}
-		refused, unnamed := ShelfCounting(raws, r.Predefined, 0, counts, known)
+		refused, waits, unnamed := shelfWaiting(raws, r.Predefined, 0, trunkCase.counts, known, trunkCase.declared)
+		for name := range waits {
+			_, refused[name] = Manifest(raws[name], r.Predefined)
+		}
+		if c.Name == TrunkCase {
+			for name, why := range trunkCase.undecoded {
+				refused[name] = append(refused[name], undecodedWords(name, why))
+			}
+		}
 		cv := composer.CaseVerdict{Name: c.Name, Manifests: map[string]composer.ManifestRead{}}
 		for name := range raws {
 			if problems := refused[name]; len(problems) > 0 {
@@ -270,34 +295,63 @@ func UseSeatList(defs []seatdef.Definition) {
 // TrunkCase is the case of a request holding the catalogue as the trunk holds it (the checker's JudgeTrunk).
 const TrunkCase = "trunk"
 
-// trunkOldSections counts the old sections the modules accepted at the trunk use, as the indexer counts them from its
-// verdicts (issue 1966 D4, ADR 0595 §11): a change is refused at the merge check exactly as at take-in (judged once, ADR
-// 0578). Nil where the request holds no trunk case, which refuses no use of a section.
-func trunkOldSections(r composer.Request) OldSectionCounts {
+// trunkRead is what the trunk case as it stands gives every case of a request (design 47 G A-337, §712, ADR 0579 §2): every
+// trunk-case manifest that decodes counts its old sections and declares its seats, accepted by this judge's rules or not, so
+// a change is refused only for what it causes and not for a trunk the new rules refuse; each that does not decode is named,
+// with why, for the trunk case's verdict.
+type trunkRead struct {
+	counts    OldSectionCounts
+	declared  trunkSeats
+	undecoded map[string]string
+}
+
+// trunkSeats are the seats the trunk case's manifests declare, by seat: the first declaring module in name order and its
+// declaration.
+type trunkSeats map[string]trunkSeat
+
+type trunkSeat struct {
+	module      string
+	declaration catalogue.SeatDeclaration
+}
+
+// readTrunk reads the request's trunk case (TrunkCase): the old sections its manifests use, as the indexer counts them from
+// its verdicts (issue 1966 D4, ADR 0595 §11), so a change is refused at the merge check exactly as at take-in (judged once,
+// ADR 0578), and the seats they declare. No count where the request holds no trunk case, which refuses no use of a section.
+func readTrunk(r composer.Request) trunkRead {
 	for _, c := range r.Cases {
 		if c.Name != TrunkCase {
 			continue
 		}
-		raws := map[string][]byte{}
-		for name, m := range c.Manifests {
-			if len(m.Raw) > 0 {
-				raws[name] = m.Raw
-			}
-		}
-		refused, _ := Shelf(raws, r.Predefined, 0)
-		var accepted []catalogue.Manifest
-		for name, raw := range raws {
-			if len(refused[name]) > 0 {
+		read := trunkRead{declared: trunkSeats{}, undecoded: map[string]string{}}
+		var decoded []catalogue.Manifest
+		for _, name := range slices.Sorted(maps.Keys(c.Manifests)) {
+			raw := c.Manifests[name].Raw
+			if len(raw) == 0 {
 				continue
 			}
-			if m, err := catalogue.Decode(raw); err == nil {
-				m.Module = name
-				accepted = append(accepted, m)
+			m, err := catalogue.Decode(raw)
+			if err != nil {
+				read.undecoded[name] = err.Error()
+				continue
+			}
+			m.Module = name
+			decoded = append(decoded, m)
+			for _, s := range m.DefinesSeats {
+				if _, taken := read.declared[s.Name]; s.Name != "" && !taken {
+					read.declared[s.Name] = trunkSeat{module: name, declaration: s}
+				}
 			}
 		}
-		return CountOldSections(accepted)
+		read.counts = CountOldSections(decoded)
+		return read
 	}
-	return nil
+	return trunkRead{}
+}
+
+// undecodedWords names a trunk-case manifest that does not decode, which counts no old section and declares no seat.
+func undecodedWords(module, why string) string {
+	return fmt.Sprintf("%s does not decode, so it counts no old section and declares no seat for the change (design 47 G "+
+		"A-337): %s", module, why)
 }
 
 var (
diff --git a/modules/mesh-delivery-indexer/judge/judge_test.go b/modules/mesh-delivery-indexer/judge/judge_test.go
index b87cf831..58f7c158 100644
--- a/modules/mesh-delivery-indexer/judge/judge_test.go
+++ b/modules/mesh-delivery-indexer/judge/judge_test.go
@@ -132,6 +132,29 @@ func TestTheJudge(t *testing.T) {
 		!got["newer"].Accepted || !got["user"].Accepted || !got["mesh-grants"].Accepted {
 		t.Errorf("the change's old sections: %+v", got)
 	}
+	// A-337 (§712, ADR 0579 §2): the trunk case as it stands counts and declares, every manifest of it that decodes, accepted
+	// by the new rules or not: a change of migrated manifests against an unmigrated trunk (version "1") refuses nothing for
+	// a count or a declarer, and a trunk manifest that does not decode is named in the trunk case's verdict.
+	unmigrated := composer.Request{V: composer.Version, Cases: []composer.Case{
+		{Name: "change", Manifests: map[string]composer.Manifest{
+			"user":     {Raw: json.RawMessage(`{"module":"user","version":"1.0","state":["x"],"seats":[{"name":"channel","scope":"mesh"}]}`)},
+			"caller":   {Raw: json.RawMessage(`{"module":"caller","version":"1.0","uses":["channel","kept"]}`)},
+			"declarer": {Raw: json.RawMessage(`{"module":"declarer","version":"1","seats":[{"name":"kept","scope":"mesh"}]}`)}}},
+		{Name: "trunk", Manifests: map[string]composer.Manifest{
+			"user":     {Raw: json.RawMessage(`{"module":"user","version":"1","state":["x"],"seats":[{"name":"channel","scope":"mesh"}]}`)},
+			"caller":   {Raw: json.RawMessage(`{"module":"caller","version":"1"}`)},
+			"declarer": {Raw: json.RawMessage(`{"module":"declarer","version":"1","seats":[{"name":"kept","scope":"mesh"}]}`)},
+			"broken":   {Raw: json.RawMessage(`{"module":"broken","version":[`)}}}}}
+	uv, err := Request(unmigrated)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := uv.Cases[0].Manifests; !got["user"].Accepted || !got["caller"].Accepted || got["declarer"].Accepted {
+		t.Errorf("a change of migrated manifests against an unmigrated trunk: %+v", got)
+	}
+	if got := uv.Cases[1].Manifests["broken"]; got.Accepted || !strings.Contains(got.Refused, "broken does not decode") {
+		t.Errorf("an undecodable trunk manifest is not named: %+v", got)
+	}
 	r.Cases[0].Manifests["c"] = composer.Manifest{Digest: strings.Repeat("a", 64)}
 	if _, err := Request(r); err == nil {
 		t.Fatal("a manifest left as a digest was judged")
diff --git a/modules/mesh-delivery-indexer/judge/rules.go b/modules/mesh-delivery-indexer/judge/rules.go
index eeb762f9..8ec70475 100644
--- a/modules/mesh-delivery-indexer/judge/rules.go
+++ b/modules/mesh-delivery-indexer/judge/rules.go
@@ -4806,6 +4806,12 @@ const meshSeatPrefix = "mesh-"
 const retiredLoginShell = "login-shell"
 
 func CatalogueProblems(shelf catalogue.Shelf) []string {
+	return catalogueProblems(shelf, nil)
+}
+
+// catalogueProblems is CatalogueProblems with the seats the trunk case declares (A-337) declared too, each a seat no module
+// of the shelf declares: a module the trunk holds and the new rules refuse still declares.
+func catalogueProblems(shelf catalogue.Shelf, trunk trunkSeats) []string {
 	var problems []string
 	// A stream name has one owner (novox/hq ADR 0363).
 	problems = append(problems, StreamNameProblems(shelf)...)
@@ -4847,6 +4853,12 @@ func CatalogueProblems(shelf catalogue.Shelf) []string {
 			declared[s.Name] = s
 		}
 	}
+	for seat, d := range trunk {
+		if _, taken := declaredBy[seat]; !taken {
+			declaredBy[seat] = d.module
+			declared[seat] = d.declaration
+		}
+	}
 
 	exists := func(seat string) bool {
 		if _, isMesh := catalogue.SeatNamed(seat); isMesh {