diff --git a/Sources/Overlays/_Testing_WinSDK/Attachments/AttachableImageFormat+CLSID.swift b/Sources/Overlays/_Testing_WinSDK/Attachments/AttachableImageFormat+CLSID.swift
index dfe04c885..f652e4a33 100644
--- a/Sources/Overlays/_Testing_WinSDK/Attachments/AttachableImageFormat+CLSID.swift
+++ b/Sources/Overlays/_Testing_WinSDK/Attachments/AttachableImageFormat+CLSID.swift
@@ -16,7 +16,7 @@ public import WinSDK
 /// }
 extension AttachableImageFormat {
   private static let _encoderPathExtensionsByCLSID = Result {
-    var result = [CLSID.Wrapper: [String]]()
+    var result = [CLSID: [String]]()
 
     // Create an imaging factory.
     let factory = try IWICImagingFactory.create()
@@ -69,7 +69,7 @@ extension AttachableImageFormat {
         continue
       }
       let extensions = _pathExtensions(for: info)
-      result[CLSID.Wrapper(clsid)] = extensions
+      result[clsid] = extensions
     }
 
     return result
@@ -136,7 +136,7 @@ extension AttachableImageFormat {
             0 == _wcsicmp(pathExtension, encoderExt)
           }
         }
-      }.map { $0.key.rawValue }
+      }.map { $0.key }
   }
 
   /// Get the `CLSID` value of the WIC image encoder corresponding to the same
@@ -172,13 +172,13 @@ extension AttachableImageFormat {
   static func appendPathExtension(for clsid: CLSID, to preferredName: String) -> String {
     // If there's already a CLSID associated with the filename, and it matches
     // the one passed to us, no changes are needed.
-    if let existingCLSID = computeEncoderCLSID(forPreferredName: preferredName), CLSID.Wrapper(clsid) == CLSID.Wrapper(existingCLSID) {
+    if let existingCLSID = computeEncoderCLSID(forPreferredName: preferredName), clsid == existingCLSID {
       return preferredName
     }
 
     // Find the preferred path extension for the encoder with the given CLSID.
     let encoderPathExtensionsByCLSID = (try? _encoderPathExtensionsByCLSID.get()) ?? [:]
-    if let ext = encoderPathExtensionsByCLSID[CLSID.Wrapper(clsid)]?.first {
+    if let ext = encoderPathExtensionsByCLSID[clsid]?.first {
       return "\(preferredName).\(ext)"
     }
 
@@ -221,12 +221,12 @@ extension AttachableImageFormat {
   ///   @Available(Swift, introduced: 6.3)
   /// }
   public init(encoderCLSID: CLSID, encodingQuality: Float = 1.0) {
-    let encoderCLSID = CLSID.Wrapper(encoderCLSID)
-    let kind: Kind = if encoderCLSID == CLSID.Wrapper(CLSID_WICPngEncoder) {
+    let kind: Kind = switch encoderCLSID {
+    case CLSID_WICPngEncoder:
       .png
-    } else if encoderCLSID == CLSID.Wrapper(CLSID_WICJpegEncoder) {
+    case CLSID_WICJpegEncoder:
       .jpeg
-    } else {
+    default:
       .systemValue(encoderCLSID)
     }
     self.init(kind: kind, encodingQuality: encodingQuality)
@@ -281,7 +281,7 @@ extension AttachableImageFormat.Kind: CustomStringConvertible, CustomDebugString
     case .jpeg:
       CLSID_WICJpegEncoder
     case let .systemValue(clsid):
-      (clsid as! CLSID.Wrapper).rawValue
+      clsid as! CLSID
     }
   }
 
@@ -308,7 +308,7 @@ extension AttachableImageFormat.Kind: CustomStringConvertible, CustomDebugString
   package var description: String {
     let clsid = encoderCLSID
     let encoderPathExtensionsByCLSID = (try? AttachableImageFormat._encoderPathExtensionsByCLSID.get()) ?? [:]
-    if let ext = encoderPathExtensionsByCLSID[CLSID.Wrapper(clsid)]?.first {
+    if let ext = encoderPathExtensionsByCLSID[clsid]?.first {
       return "\(ext.uppercased()) format"
     }
     return Self._description(of: clsid)
@@ -318,7 +318,7 @@ extension AttachableImageFormat.Kind: CustomStringConvertible, CustomDebugString
     let clsid = encoderCLSID
     let clsidDescription = Self._description(of: clsid)
     let encoderPathExtensionsByCLSID = (try? AttachableImageFormat._encoderPathExtensionsByCLSID.get()) ?? [:]
-    if let ext = encoderPathExtensionsByCLSID[CLSID.Wrapper(clsid)]?.first {
+    if let ext = encoderPathExtensionsByCLSID[clsid]?.first {
       return "\(ext.uppercased()) format (\(clsidDescription))"
     }
     return clsidDescription
diff --git a/Sources/Overlays/_Testing_WinSDK/Support/Additions/GUIDAdditions.swift b/Sources/Overlays/_Testing_WinSDK/Support/Additions/GUIDAdditions.swift
index 06985ed4c..95796785a 100644
--- a/Sources/Overlays/_Testing_WinSDK/Support/Additions/GUIDAdditions.swift
+++ b/Sources/Overlays/_Testing_WinSDK/Support/Additions/GUIDAdditions.swift
@@ -8,48 +8,24 @@
 // See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 //
 
-#if os(Windows)
-internal import WinSDK
+#if compiler(<6.3) && os(Windows)
+public import WinSDK
 
-extension GUID {
-  /// A type that wraps `GUID` instances and conforms to various Swift
-  /// protocols.
-  ///
-  /// - Bug: This type will become obsolete once we can use the `Equatable` and
-  ///   `Hashable` conformances added to the WinSDK module in Swift 6.3.
-#if compiler(>=6.3.1) && DEBUG
-  @available(*, deprecated, message: "GUID.Wrapper is no longer needed and can be removed.")
-#endif
-  struct Wrapper: Sendable, RawRepresentable {
-    var rawValue: GUID
-  }
-}
-
-// MARK: -
-
-extension GUID.Wrapper: Equatable, Hashable, CustomStringConvertible {
-  init(_ rawValue: GUID) {
-    self.init(rawValue: rawValue)
-  }
-
-#if compiler(<6.3.1)
+extension GUID: @retroactive Equatable, @retroactive Hashable {
   private var _uint128Value: UInt128 {
-    withUnsafeBytes(of: rawValue) { buffer in
+    withUnsafeBytes(of: self) { buffer in
       buffer.baseAddress!.loadUnaligned(as: UInt128.self)
     }
   }
 
-  static func ==(lhs: Self, rhs: Self) -> Bool {
+  // SEE: https://github.com/swiftlang/swift/pull/85196
+  @_implements(Equatable, ==(_:_:))
+  public static func __equals(lhs: Self, rhs: Self) -> Bool {
     lhs._uint128Value == rhs._uint128Value
   }
 
-  func hash(into hasher: inout Hasher) {
+  public func hash(into hasher: inout Hasher) {
     hasher.combine(_uint128Value)
   }
-
-  var description: String {
-    String(describing: rawValue)
-  }
-#endif
 }
 #endif