diff --git a/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved b/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
index e227c65b8..545bf4c6f 100644
--- a/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
+++ b/Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -1,5 +1,5 @@
 {
-  "originHash" : "34ec164994f4a7193f54a6829aeb133fff6d99ebe00bfbf67e2ac554c7ea9724",
+  "originHash" : "254d984aabc648722f4c902579675ea8e2c937654a313255c58df9d25e209369",
   "pins" : [
     {
       "identity" : "equatable",
@@ -10,24 +10,6 @@
         "revision" : "8f1dccead65d97173ed695c6c1ba9d0570d35619"
       }
     },
-    {
-      "identity" : "opencoregraphics",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/OpenSwiftUIProject/OpenCoreGraphics",
-      "state" : {
-        "branch" : "main",
-        "revision" : "8d63c405f565fb287042e0b8dc3bf0c4b8b2b56f"
-      }
-    },
-    {
-      "identity" : "openobservation",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/OpenSwiftUIProject/OpenObservation",
-      "state" : {
-        "branch" : "main",
-        "revision" : "814dbe008056db6007bfc3d27fe585837f30e9ed"
-      }
-    },
     {
       "identity" : "swift-custom-dump",
       "kind" : "remoteSourceControl",
diff --git a/Example/SharedExample/ContentView.swift b/Example/SharedExample/ContentView.swift
index 3695c64f4..68e8c215b 100644
--- a/Example/SharedExample/ContentView.swift
+++ b/Example/SharedExample/ContentView.swift
@@ -13,6 +13,6 @@ import SwiftUI
 
 struct ContentView: View {
     var body: some View {
-        FlowerView()
+        Image(systemName: "gear")
     }
 }
diff --git a/Package.swift b/Package.swift
index 84a1975d0..27af3e2c5 100644
--- a/Package.swift
+++ b/Package.swift
@@ -145,7 +145,7 @@ let releaseVersion = envIntValue("TARGET_RELEASE", default: 2024)
 let libraryEvolutionCondition = envBoolValue("LIBRARY_EVOLUTION", default: buildForDarwinPlatform)
 let compatibilityTestCondition = envBoolValue("COMPATIBILITY_TEST")
 
-let useLocalDeps = envBoolValue("USE_LOCAL_DEPS")
+let useLocalDeps = envBoolValue("USE_LOCAL_DEPS", default: true)
 
 // For OpenAttributeGraphShims
 let computeCondition = envBoolValue("OPENATTRIBUTESHIMS_COMPUTE", default: false)
diff --git a/Sources/OpenSwiftUICore/Data/Protobuf/Foundation+ProtobufMessage.swift b/Sources/OpenSwiftUICore/Data/Protobuf/Foundation+ProtobufMessage.swift
new file mode 100644
index 000000000..3c6b935ba
--- /dev/null
+++ b/Sources/OpenSwiftUICore/Data/Protobuf/Foundation+ProtobufMessage.swift
@@ -0,0 +1,107 @@
+//
+//  Foundation+ProtobufMessage.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: WIP
+//  Note: Data archiveWriter/archiveReader deduplication not yet implemented
+
+package import Foundation
+
+// MARK: - URL + ProtobufMessage
+
+extension URL: ProtobufMessage {
+    package func encode(to encoder: inout ProtobufEncoder) throws {
+        try encoder.stringField(1, relativeString)
+        if let baseURL {
+            try encoder.messageField(2, baseURL)
+        }
+    }
+
+    package init(from decoder: inout ProtobufDecoder) throws {
+        var relativeString = ""
+        var baseURL: URL? = nil
+        while let field = try decoder.nextField() {
+            switch field.tag {
+            case 1: relativeString = try decoder.stringField(field)
+            case 2: baseURL = try decoder.messageField(field)
+            default: try decoder.skipField(field)
+            }
+        }
+        guard let url = URL(string: relativeString, relativeTo: baseURL) else {
+            throw ProtobufDecoder.DecodingError.failed
+        }
+        self = url
+    }
+}
+
+// MARK: - UUID + ProtobufMessage
+
+extension UUID: ProtobufMessage {
+    package func encode(to encoder: inout ProtobufEncoder) throws {
+        withUnsafeBytes(of: uuid) { buffer in
+            encoder.dataField(1, buffer)
+        }
+    }
+
+    package init(from decoder: inout ProtobufDecoder) throws {
+        var uuidBytes: uuid_t = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+        while let field = try decoder.nextField() {
+            switch field.tag {
+            case 1:
+                let buffer = try decoder.dataBufferField(field)
+                guard buffer.count == 16, let src = buffer.baseAddress else {
+                    throw ProtobufDecoder.DecodingError.failed
+                }
+                withUnsafeMutableBytes(of: &uuidBytes) { $0.baseAddress!.copyMemory(from: src, byteCount: 16) }
+            default:
+                try decoder.skipField(field)
+            }
+        }
+        self = UUID(uuid: uuidBytes)
+    }
+}
+
+// MARK: - Data + ProtobufMessage [WIP]
+
+extension Data: ProtobufMessage {
+    package func encode(to encoder: inout ProtobufEncoder) throws {
+        if /*let archiveWriter*/ false {
+            // TODO
+            _openSwiftUIUnreachableCode()
+        } else {
+            encoder.dataField(2, self)
+        }
+    }
+
+    package init(from decoder: inout ProtobufDecoder) throws {
+        self = Data()
+        while let field = try decoder.nextField() {
+            switch field.tag {
+            case 2:
+                self = try decoder.dataField(field)
+            default:
+                try decoder.skipField(field)
+            }
+        }
+    }
+}
+
+// MARK: - Locale + ProtobufMessage
+
+extension Locale: ProtobufMessage {
+    package func encode(to encoder: inout ProtobufEncoder) throws {
+        try encoder.stringField(1, identifier)
+    }
+
+    package init(from decoder: inout ProtobufDecoder) throws {
+        var identifier = ""
+        while let field = try decoder.nextField() {
+            switch field.tag {
+            case 1: identifier = try decoder.stringField(field)
+            default: try decoder.skipField(field)
+            }
+        }
+        self = Locale(identifier: identifier)
+    }
+}
diff --git a/Sources/OpenSwiftUISymbolDualTestsSupport/Data/Protobuf/FoundationProtobufMessageTestsStub.c b/Sources/OpenSwiftUISymbolDualTestsSupport/Data/Protobuf/FoundationProtobufMessageTestsStub.c
new file mode 100644
index 000000000..8a2476280
--- /dev/null
+++ b/Sources/OpenSwiftUISymbolDualTestsSupport/Data/Protobuf/FoundationProtobufMessageTestsStub.c
@@ -0,0 +1,26 @@
+//
+//  FoundationProtobufMessageTestsStub.c
+//  OpenSwiftUISymbolDualTestsSupport
+
+#include "OpenSwiftUIBase.h"
+
+#if OPENSWIFTUI_TARGET_OS_DARWIN
+#import <SymbolLocator.h>
+
+// URL
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_URLEncode, SwiftUICore, $s10Foundation3URLV7SwiftUIE6encode2toyAD15ProtobufEncoderVz_tKF);
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_URLDecode, SwiftUICore, $s10Foundation3URLV7SwiftUIE4fromAcD15ProtobufDecoderVz_tKcfC);
+
+// UUID
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_UUIDEncode, SwiftUICore, $s10Foundation4UUIDV7SwiftUIE6encode2toyAD15ProtobufEncoderVz_tKF);
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_UUIDDecode, SwiftUICore, $s10Foundation4UUIDV7SwiftUIE4fromAcD15ProtobufDecoderVz_tKcfC);
+
+// Data
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_DataEncode, SwiftUICore, $s10Foundation4DataV7SwiftUIE6encode2toyAD15ProtobufEncoderVz_tKF);
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_DataDecode, SwiftUICore, $s10Foundation4DataV7SwiftUIE4fromAcD15ProtobufDecoderVz_tKcfC);
+
+// Locale
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_LocaleEncode, SwiftUICore, $s10Foundation6LocaleV7SwiftUIE6encode2toyAD15ProtobufEncoderVz_tKF);
+DEFINE_SL_STUB_SLF(OpenSwiftUITestStub_LocaleDecode, SwiftUICore, $s10Foundation6LocaleV7SwiftUIE4fromAcD15ProtobufDecoderVz_tKcfC);
+
+#endif
diff --git a/Tests/OpenSwiftUISymbolDualTests/Data/Protobuf/FoundationProtobufMessageDualTests.swift b/Tests/OpenSwiftUISymbolDualTests/Data/Protobuf/FoundationProtobufMessageDualTests.swift
new file mode 100644
index 000000000..73d2bd750
--- /dev/null
+++ b/Tests/OpenSwiftUISymbolDualTests/Data/Protobuf/FoundationProtobufMessageDualTests.swift
@@ -0,0 +1,196 @@
+//
+//  FoundationProtobufMessageDualTests.swift
+//  OpenSwiftUISymbolDualTests
+
+#if canImport(SwiftUI, _underlyingVersion: 6.5.4)
+import Foundation
+import OpenSwiftUICore
+import OpenSwiftUITestsSupport
+import Testing
+
+// MARK: - @_silgen_name declarations
+
+extension URL {
+    @_silgen_name("OpenSwiftUITestStub_URLEncode")
+    func swiftUI_encode(to encoder: inout ProtobufEncoder) throws
+
+    @_silgen_name("OpenSwiftUITestStub_URLDecode")
+    init(swiftUI_from decoder: inout ProtobufDecoder) throws
+}
+
+extension UUID {
+    @_silgen_name("OpenSwiftUITestStub_UUIDEncode")
+    func swiftUI_encode(to encoder: inout ProtobufEncoder) throws
+
+    @_silgen_name("OpenSwiftUITestStub_UUIDDecode")
+    init(swiftUI_from decoder: inout ProtobufDecoder) throws
+}
+
+extension Data {
+    @_silgen_name("OpenSwiftUITestStub_DataEncode")
+    func swiftUI_encode(to encoder: inout ProtobufEncoder) throws
+
+    @_silgen_name("OpenSwiftUITestStub_DataDecode")
+    init(swiftUI_from decoder: inout ProtobufDecoder) throws
+}
+
+extension Locale {
+    @_silgen_name("OpenSwiftUITestStub_LocaleEncode")
+    func swiftUI_encode(to encoder: inout ProtobufEncoder) throws
+
+    @_silgen_name("OpenSwiftUITestStub_LocaleDecode")
+    init(swiftUI_from decoder: inout ProtobufDecoder) throws
+}
+
+// MARK: - Tests
+
+@Suite
+struct FoundationProtobufMessageDualTests {
+    @Suite
+    struct URLTests {
+        @Test(
+            arguments: [
+                (
+                    URL(string: "https://example.com")!,
+                    "0a1368747470733a2f2f6578616d706c652e636f6d"
+                ),
+                (
+                    URL(string: "path", relativeTo: URL(string: "https://example.com"))!,
+                    "0a04706174681215 0a1368747470733a2f2f6578616d706c652e636f6d"
+                        .replacingOccurrences(of: " ", with: "")
+                ),
+            ]
+        )
+        func pbMessage(url: URL, hexString: String) throws {
+            try url.testPBEncoding(hexString: hexString)
+            try url.testPBDecoding(hexString: hexString)
+            try url.testPBEncoding(swiftUI_hexString: hexString)
+            try url.testPBDecoding(swiftUI_hexString: hexString)
+        }
+    }
+
+    @Suite
+    struct UUIDTests {
+        @Test(
+            arguments: [
+                (
+                    UUID(uuidString: "E621E1F8-C36C-495A-93FC-0C247A3E6E5F")!,
+                    "0a10e621e1f8c36c495a93fc0c247a3e6e5f"
+                ),
+            ]
+        )
+        func pbMessage(uuid: UUID, hexString: String) throws {
+            try uuid.testPBEncoding(hexString: hexString)
+            try uuid.testPBDecoding(hexString: hexString)
+            try uuid.testPBEncoding(swiftUI_hexString: hexString)
+            try uuid.testPBDecoding(swiftUI_hexString: hexString)
+        }
+    }
+
+    @Suite
+    struct DataTests {
+        @Test(
+            arguments: [
+                (Data(), ""),
+                (Data([0x48, 0x65, 0x6c, 0x6c, 0x6f]), "120548656c6c6f"),
+            ]
+        )
+        func pbMessage(data: Data, hexString: String) throws {
+            try data.testPBEncoding(hexString: hexString)
+            try data.testPBDecoding(hexString: hexString)
+            try data.testPBEncoding(swiftUI_hexString: hexString)
+            try data.testPBDecoding(swiftUI_hexString: hexString)
+        }
+    }
+
+    @Suite
+    struct LocaleTests {
+        @Test(
+            arguments: [
+                (Locale(identifier: "en_US"), "0a05656e5f5553"),
+            ]
+        )
+        func pbMessage(locale: Locale, hexString: String) throws {
+            try locale.testPBEncoding(hexString: hexString)
+            try locale.testPBDecoding(hexString: hexString)
+            try locale.testPBEncoding(swiftUI_hexString: hexString)
+            try locale.testPBDecoding(swiftUI_hexString: hexString)
+        }
+    }
+}
+
+// MARK: - SwiftUI Dual Test Helpers
+
+extension URL {
+    func testPBEncoding(swiftUI_hexString expectedHexString: String) throws {
+        let data = try ProtobufEncoder.encoding { encoder in
+            try swiftUI_encode(to: &encoder)
+        }
+        #expect(data.hexString == expectedHexString)
+    }
+
+    func testPBDecoding(swiftUI_hexString hexString: String) throws {
+        guard let data = Data(hexString: hexString) else {
+            throw ProtobufDecoder.DecodingError.failed
+        }
+        var decoder = ProtobufDecoder(data)
+        let decoded = try URL(swiftUI_from: &decoder)
+        #expect(decoded == self)
+    }
+}
+
+extension UUID {
+    func testPBEncoding(swiftUI_hexString expectedHexString: String) throws {
+        let data = try ProtobufEncoder.encoding { encoder in
+            try swiftUI_encode(to: &encoder)
+        }
+        #expect(data.hexString == expectedHexString)
+    }
+
+    func testPBDecoding(swiftUI_hexString hexString: String) throws {
+        guard let data = Data(hexString: hexString) else {
+            throw ProtobufDecoder.DecodingError.failed
+        }
+        var decoder = ProtobufDecoder(data)
+        let decoded = try UUID(swiftUI_from: &decoder)
+        #expect(decoded == self)
+    }
+}
+
+extension Data {
+    func testPBEncoding(swiftUI_hexString expectedHexString: String) throws {
+        let data = try ProtobufEncoder.encoding { encoder in
+            try swiftUI_encode(to: &encoder)
+        }
+        #expect(data.hexString == expectedHexString)
+    }
+
+    func testPBDecoding(swiftUI_hexString hexString: String) throws {
+        guard let data = Data(hexString: hexString) else {
+            throw ProtobufDecoder.DecodingError.failed
+        }
+        var decoder = ProtobufDecoder(data)
+        let decoded = try Data(swiftUI_from: &decoder)
+        #expect(decoded == self)
+    }
+}
+
+extension Locale {
+    func testPBEncoding(swiftUI_hexString expectedHexString: String) throws {
+        let data = try ProtobufEncoder.encoding { encoder in
+            try swiftUI_encode(to: &encoder)
+        }
+        #expect(data.hexString == expectedHexString)
+    }
+
+    func testPBDecoding(swiftUI_hexString hexString: String) throws {
+        guard let data = Data(hexString: hexString) else {
+            throw ProtobufDecoder.DecodingError.failed
+        }
+        var decoder = ProtobufDecoder(data)
+        let decoded = try Locale(swiftUI_from: &decoder)
+        #expect(decoded == self)
+    }
+}
+
+#endif