diff --git a/bitchatTests/LocalizationCoverageTests.swift b/bitchatTests/LocalizationCoverageTests.swift
index 8748b960a5..29bea3b84b 100644
--- a/bitchatTests/LocalizationCoverageTests.swift
+++ b/bitchatTests/LocalizationCoverageTests.swift
@@ -71,43 +71,139 @@ struct LocalizationCoverageTests {
     }
 
     /// The catalog tests above validate the CATALOG; this one validates the
-    /// CODE. A `String(localized:)` whose key is absent from every catalog
-    /// compiles and runs fine — it just silently ships its English
-    /// `defaultValue` to all 29 non-source locales. That blind spot let the
-    /// entire notices/board composer (10 keys), two delivery states, and two
-    /// media-failure reasons go untranslated while the coverage tests stayed
-    /// green. Interpolated keys can't be checked statically and are skipped;
-    /// every literal key must resolve.
-    @Test func everyCodeReferencedKeyExistsInACatalog() throws {
-        let main = try Self.loadCatalog("bitchat/Localizable.xcstrings")
-        let shareExt = try Self.loadCatalog("bitchatShareExtension/Localization/Localizable.xcstrings")
-        let knownKeys = Set(main.coverage.keys).union(shareExt.coverage.keys)
+    /// CODE. A `String(localized:)` whose key is absent from the catalog its
+    /// target actually ships compiles and runs fine — it just silently ships
+    /// its English `defaultValue` to all 29 non-source locales. That blind
+    /// spot let the entire notices/board composer (10 keys), two delivery
+    /// states, and two media-failure reasons go untranslated while the
+    /// coverage tests stayed green. Interpolated keys can't be checked
+    /// statically and are skipped; every literal key must resolve.
+    ///
+    /// The catalogs are checked per target, not as a union: the share
+    /// extension bundles only its own catalog, so a key it references that
+    /// lives solely in the app catalog is just as untranslated there as one
+    /// that exists nowhere.
+    @Test func everyCodeReferencedKeyExistsInItsOwnCatalog() throws {
+        let main = try Self.loadCatalog(Self.mainCatalogPath)
+        let shareExt = try Self.loadCatalog(Self.shareExtensionCatalogPath)
+        let mainKeys = Set(main.coverage.keys)
+        let shareKeys = Set(shareExt.coverage.keys)
 
-        let pattern = try NSRegularExpression(pattern: #"String\(\s*localized:\s*"([^"\\]+)""#)
-        var missing: [String] = []
-
-        for sourceRoot in ["bitchat", "bitchatShareExtension"] {
-            let rootURL = Self.repoRoot.appendingPathComponent(sourceRoot)
-            let enumerator = try #require(FileManager.default.enumerator(
-                at: rootURL,
-                includingPropertiesForKeys: nil
-            ))
-            for case let fileURL as URL in enumerator where fileURL.pathExtension == "swift" {
-                let source = try String(contentsOf: fileURL, encoding: .utf8)
-                let range = NSRange(source.startIndex..., in: source)
-                pattern.enumerateMatches(in: source, range: range) { match, _, _ in
-                    guard let match, let keyRange = Range(match.range(at: 1), in: source) else { return }
-                    let key = String(source[keyRange])
-                    if !knownKeys.contains(key) {
-                        missing.append("\(key) (\(fileURL.lastPathComponent))")
-                    }
+        // Files under `bitchat/` that the share extension also compiles have to
+        // resolve in both catalogs, since each target bundles only its own.
+        let sharedSources = try Self.shareExtensionMembershipExceptions()
+
+        for (sourceRoot, ownKeys, otherKeys, ownCatalog, otherCatalog) in [
+            ("bitchat", mainKeys, shareKeys, Self.mainCatalogPath, Self.shareExtensionCatalogPath),
+            ("bitchatShareExtension", shareKeys, mainKeys,
+             Self.shareExtensionCatalogPath, Self.mainCatalogPath)
+        ] {
+            let references = try Self.localizedKeyReferences(in: sourceRoot)
+
+            let missing = references
+                .filter { !ownKeys.contains($0.key) }
+                .map { reference -> String in
+                    let note = otherKeys.contains(reference.key)
+                        ? " (present in \(otherCatalog), which this target does not bundle)"
+                        : " (present in no catalog)"
+                    return "\(reference.location) \(reference.key)\(note)"
                 }
-            }
+
+            #expect(
+                missing.isEmpty,
+                """
+                keys referenced under \(sourceRoot)/ but absent from \(ownCatalog) — \
+                these ship English to all non-source locales:
+                \(missing.sorted().joined(separator: "\n"))
+                """
+            )
+
+            guard sourceRoot == "bitchat" else { continue }
+            let missingInBoth = references
+                .filter { sharedSources.contains($0.location.prefix(while: { $0 != ":" }).description) }
+                .filter { !shareKeys.contains($0.key) }
+                .map { "\($0.location) \($0.key)" }
+
+            #expect(
+                missingInBoth.isEmpty,
+                """
+                keys referenced from files the share extension also compiles, but absent \
+                from \(Self.shareExtensionCatalogPath) — these ship English inside the \
+                extension:
+                \(missingInBoth.sorted().joined(separator: "\n"))
+                """
+            )
         }
+    }
 
-        #expect(
-            missing.isEmpty,
-            "keys referenced in code but absent from every catalog — these ship English to all non-source locales: \(missing.sorted().joined(separator: ", "))"
+    /// The files under `bitchat/` that the share-extension target compiles, read
+    /// from the project's membership exceptions so this cannot drift when the
+    /// set changes.
+    private static func shareExtensionMembershipExceptions() throws -> Set<String> {
+        let project = try String(
+            contentsOf: repoRoot.appendingPathComponent("bitchat.xcodeproj/project.pbxproj"),
+            encoding: .utf8
         )
+        let marker = #"Exceptions for "bitchat" folder in "bitchatShareExtension" target"#
+        guard let markerRange = project.range(of: marker),
+              let listStart = project.range(
+                of: "membershipExceptions = (", range: markerRange.upperBound..<project.endIndex
+              ),
+              let listEnd = project.range(
+                of: ");", range: listStart.upperBound..<project.endIndex
+              )
+        else { return [] }
+
+        return Set(
+            project[listStart.upperBound..<listEnd.lowerBound]
+                .split(separator: ",")
+                .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+                .filter { $0.hasSuffix(".swift") }
+                .map { "bitchat/\($0)" }
+        )
+    }
+
+    private static let mainCatalogPath = "bitchat/Localizable.xcstrings"
+    private static let shareExtensionCatalogPath =
+        "bitchatShareExtension/Localization/Localizable.xcstrings"
+
+    /// A literal `String(localized:)` key, with where it was written.
+    private struct KeyReference {
+        let key: String
+        /// `path/to/File.swift:line`, relative to the repository root.
+        let location: String
+    }
+
+    /// Every literal `String(localized:)` key under `sourceRoot`, with its
+    /// repo-relative file and line so a failure points at the call site
+    /// instead of just naming a file.
+    private static func localizedKeyReferences(in sourceRoot: String) throws -> [KeyReference] {
+        let pattern = try NSRegularExpression(pattern: #"String\(\s*localized:\s*"([^"\\]+)""#)
+        let rootURL = repoRoot.appendingPathComponent(sourceRoot)
+        let enumerator = try #require(FileManager.default.enumerator(
+            at: rootURL,
+            includingPropertiesForKeys: nil
+        ))
+
+        var references: [KeyReference] = []
+        for case let fileURL as URL in enumerator where fileURL.pathExtension == "swift" {
+            let source = try String(contentsOf: fileURL, encoding: .utf8)
+            let relativePath = fileURL.path.replacingOccurrences(
+                of: repoRoot.path + "/", with: ""
+            )
+            let range = NSRange(source.startIndex..., in: source)
+            pattern.enumerateMatches(in: source, range: range) { match, _, _ in
+                guard let match,
+                      let keyRange = Range(match.range(at: 1), in: source),
+                      let matchStart = Range(match.range, in: source)?.lowerBound
+                else { return }
+                let line = source[source.startIndex..<matchStart].count(where: { $0 == "\n" }) + 1
+                references.append(KeyReference(
+                    key: String(source[keyRange]),
+                    location: "\(relativePath):\(line)"
+                ))
+            }
+        }
+        return references
     }
 }