diff --git a/.editorconfig b/.editorconfig
index f9e5f815a..30a99e77b 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -1,3 +1,13 @@
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024-2025 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+
 # EditorConfig documentation: https://editorconfig.org
 
 root = true
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 306ab13bd..c0049b554 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -23,7 +23,6 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
       license_header_check_project_name: "Swift"
-      license_header_check_enabled: false
       docs_check_enabled: false
       unacceptable_language_check_enabled: false
       format_check_enabled: false
diff --git a/.license_header_template b/.license_header_template
new file mode 100644
index 000000000..d99c3c0f0
--- /dev/null
+++ b/.license_header_template
@@ -0,0 +1,9 @@
+@@
+@@ This source file is part of the Swift.org open source project
+@@
+@@ Copyright (c) YEARS Apple Inc. and the Swift project authors
+@@ Licensed under Apache License v2.0 with Runtime Library Exception
+@@
+@@ See https://swift.org/LICENSE.txt for license information
+@@ See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+@@
diff --git a/.licenseignore b/.licenseignore
new file mode 100644
index 000000000..b73b15c97
--- /dev/null
+++ b/.licenseignore
@@ -0,0 +1,4 @@
+Package.swift
+**/*.xctestplan
+**/*.xcscheme
+**/*.swiftoverlay
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 38aeda617..2f2828d49 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 cmake_minimum_required(VERSION 3.19.6...3.29)
 
diff --git a/Dockerfile b/Dockerfile
index d18db2add..1647b0808 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2023 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See https://swift.org/LICENSE.txt for license information
-# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2023 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 FROM swiftlang/swift:nightly-main-jammy
 
diff --git a/Sources/CMakeLists.txt b/Sources/CMakeLists.txt
index c6575a310..09e5e9fd6 100644
--- a/Sources/CMakeLists.txt
+++ b/Sources/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 set(SwiftTesting_MACRO "<auto>" CACHE STRING
     "Path to SwiftTesting macro plugin, or '<auto>' for automatically building it")
diff --git a/Sources/Overlays/CMakeLists.txt b/Sources/Overlays/CMakeLists.txt
index d4a0e75f2..434b4d3ec 100644
--- a/Sources/Overlays/CMakeLists.txt
+++ b/Sources/Overlays/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_subdirectory(_Testing_AppKit)
 add_subdirectory(_Testing_CoreGraphics)
diff --git a/Sources/Overlays/_Testing_AppKit/CMakeLists.txt b/Sources/Overlays/_Testing_AppKit/CMakeLists.txt
index 75a463433..e864509f4 100644
--- a/Sources/Overlays/_Testing_AppKit/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_AppKit/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 if (CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   add_library(_Testing_AppKit
diff --git a/Sources/Overlays/_Testing_CoreGraphics/CMakeLists.txt b/Sources/Overlays/_Testing_CoreGraphics/CMakeLists.txt
index 335068a0b..fcd1d3459 100644
--- a/Sources/Overlays/_Testing_CoreGraphics/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_CoreGraphics/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 if(APPLE)
   add_library(_Testing_CoreGraphics
diff --git a/Sources/Overlays/_Testing_CoreImage/CMakeLists.txt b/Sources/Overlays/_Testing_CoreImage/CMakeLists.txt
index baa50537e..8c8076b8b 100644
--- a/Sources/Overlays/_Testing_CoreImage/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_CoreImage/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 if(APPLE)
   add_library(_Testing_CoreImage
diff --git a/Sources/Overlays/_Testing_Foundation/CMakeLists.txt b/Sources/Overlays/_Testing_Foundation/CMakeLists.txt
index 9343960ab..7da6f773d 100644
--- a/Sources/Overlays/_Testing_Foundation/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_Foundation/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_library(_Testing_Foundation
   Attachments/_AttachableURLWrapper.swift
diff --git a/Sources/Overlays/_Testing_UIKit/CMakeLists.txt b/Sources/Overlays/_Testing_UIKit/CMakeLists.txt
index 5976e2e86..e6f4ae9d5 100644
--- a/Sources/Overlays/_Testing_UIKit/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_UIKit/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 if(APPLE)
   add_library(_Testing_UIKit
diff --git a/Sources/Overlays/_Testing_WinSDK/CMakeLists.txt b/Sources/Overlays/_Testing_WinSDK/CMakeLists.txt
index 4dcbc706e..a1df6bd60 100644
--- a/Sources/Overlays/_Testing_WinSDK/CMakeLists.txt
+++ b/Sources/Overlays/_Testing_WinSDK/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 if (CMAKE_SYSTEM_NAME STREQUAL "Windows")
   add_library(_Testing_WinSDK
diff --git a/Sources/Testing/CMakeLists.txt b/Sources/Testing/CMakeLists.txt
index f895996be..8fef166c7 100644
--- a/Sources/Testing/CMakeLists.txt
+++ b/Sources/Testing/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_library(Testing
   ABI/EntryPoints/ABIEntryPoint.swift
diff --git a/Sources/TestingMacros/CMakeLists.txt b/Sources/TestingMacros/CMakeLists.txt
index 46be5e388..9de696920 100644
--- a/Sources/TestingMacros/CMakeLists.txt
+++ b/Sources/TestingMacros/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 cmake_minimum_required(VERSION 3.19.6...3.29)
 
diff --git a/Sources/_TestDiscovery/CMakeLists.txt b/Sources/_TestDiscovery/CMakeLists.txt
index 7d6059792..7da7e0a8c 100644
--- a/Sources/_TestDiscovery/CMakeLists.txt
+++ b/Sources/_TestDiscovery/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2023–2025 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_library(_TestDiscovery STATIC
   Additions/WinSDKAdditions.swift
diff --git a/Sources/_TestingInternals/CMakeLists.txt b/Sources/_TestingInternals/CMakeLists.txt
index 2b385cb1b..90ad424e9 100644
--- a/Sources/_TestingInternals/CMakeLists.txt
+++ b/Sources/_TestingInternals/CMakeLists.txt
@@ -3,8 +3,8 @@
 # Copyright (c) 2024 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 set(CMAKE_CXX_SCAN_FOR_MODULES 0)
 
diff --git a/Tests/TestingTests/ObjCInteropTests.swift b/Tests/TestingTests/ObjCInteropTests.swift
index be12e520d..9c6e42a49 100644
--- a/Tests/TestingTests/ObjCInteropTests.swift
+++ b/Tests/TestingTests/ObjCInteropTests.swift
@@ -1,12 +1,12 @@
-/*
- This source file is part of the Swift.org open source project
-
- Copyright (c) 2023 Apple Inc. and the Swift project authors
- Licensed under Apache License v2.0 with Runtime Library Exception
-
- See https://swift.org/LICENSE.txt for license information
- See https://swift.org/CONTRIBUTORS.txt for Swift project authors
- */
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
 
 #if canImport(XCTest)
 import XCTest
diff --git a/cmake/modules/GitCommit.cmake b/cmake/modules/GitCommit.cmake
index 86b0b4733..1e5a286cf 100644
--- a/cmake/modules/GitCommit.cmake
+++ b/cmake/modules/GitCommit.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024–2025 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 find_package(Git QUIET)
 if(Git_FOUND)
diff --git a/cmake/modules/LibraryVersion.cmake b/cmake/modules/LibraryVersion.cmake
index 32901365a..72e42e4cb 100644
--- a/cmake/modules/LibraryVersion.cmake
+++ b/cmake/modules/LibraryVersion.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 # The current version of the Swift Testing release. For release branches,
 # remember to remove -dev.
diff --git a/cmake/modules/PlatformInfo.cmake b/cmake/modules/PlatformInfo.cmake
index 94c60ef28..13eb736c5 100644
--- a/cmake/modules/PlatformInfo.cmake
+++ b/cmake/modules/PlatformInfo.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2025 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2025 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 set(print_target_info_invocation "${CMAKE_Swift_COMPILER}" -print-target-info)
 if(CMAKE_Swift_COMPILER_TARGET)
diff --git a/cmake/modules/SwiftModuleInstallation.cmake b/cmake/modules/SwiftModuleInstallation.cmake
index f9bade57d..6947bb1cd 100644
--- a/cmake/modules/SwiftModuleInstallation.cmake
+++ b/cmake/modules/SwiftModuleInstallation.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 function(_swift_testing_install_target module)
   install(TARGETS ${module}
diff --git a/cmake/modules/TargetTriple.cmake b/cmake/modules/TargetTriple.cmake
index e087cc47c..39d17bc2a 100644
--- a/cmake/modules/TargetTriple.cmake
+++ b/cmake/modules/TargetTriple.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 # Ask the Swift compiler what target triple it will be compiling with today.
 set(SWT_TARGET_INFO_COMMAND "${CMAKE_Swift_COMPILER}" -print-target-info)
diff --git a/cmake/modules/shared/AvailabilityDefinitions.cmake b/cmake/modules/shared/AvailabilityDefinitions.cmake
index 2124a32be..472b2b929 100644
--- a/cmake/modules/shared/AvailabilityDefinitions.cmake
+++ b/cmake/modules/shared/AvailabilityDefinitions.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 # Settings which define commonly-used OS availability macros.
 add_compile_options(
diff --git a/cmake/modules/shared/CompilerSettings.cmake b/cmake/modules/shared/CompilerSettings.cmake
index a667f5ba1..ae9ee8fce 100644
--- a/cmake/modules/shared/CompilerSettings.cmake
+++ b/cmake/modules/shared/CompilerSettings.cmake
@@ -1,10 +1,12 @@
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2024 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See http://swift.org/LICENSE.txt for license information
-# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2024 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+##
 
 # Settings intended to be applied to every Swift target in this project.
 # Analogous to project-level build settings in an Xcode project.