diff --git a/src/mail/replies.ts b/src/mail/replies.ts
index ecc2a44..80930e3 100644
--- a/src/mail/replies.ts
+++ b/src/mail/replies.ts
@@ -1,3 +1,10 @@
+// Adapted from the GitHub email_reply_parser library, which is licensed
+// permissively under the terms of the MIT license.
+// https://github.com/github/email_reply_parser/
+
+// Modifications focus on rewriting as TypeScript and improving support
+// for parsing lightly formatted HTML messages.
+
 // EmailReplyParser is a library to parse plain text email content.
 // The goal is to identify quoted text, signatures, or original content.