diff --git a/readme.md b/readme.md
index 2a4a615..68d5775 100644
--- a/readme.md
+++ b/readme.md
@@ -36,7 +36,7 @@ as long as caution is taken to avoid a mismatch between the project's stability
 level and the required stability and maintainability of your own project.
 
 Metamorphose is designed to be _small_. Its entire source code currently consists
-of 218 lines of code.
+of 223 lines of code.
 
 ## Building
 
diff --git a/src/core/soundness+metamorphose-core.scala b/src/core/soundness+metamorphose-core.scala
index 3cc63ef..c0c7ea2 100644
--- a/src/core/soundness+metamorphose-core.scala
+++ b/src/core/soundness+metamorphose-core.scala
@@ -1,3 +1,19 @@
+/*
+    Metamorphose, version [unreleased]. Copyright 2024 Jon Pretty, Propensive OÜ.
+
+    The primary distribution site is: https://propensive.com/
+
+    Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
+    file except in compliance with the License. You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software distributed under the
+    License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+    either express or implied. See the License for the specific language governing permissions
+    and limitations under the License.
+*/
+
 package soundness
 
 export metamorphose.{Factoradic, Factorial, Permutation, PermutationError}