diff --git a/unified/ql/lib/unified.qll b/unified/ql/lib/unified.qll
index 5b073290acf..4f7387ef8f1 100644
--- a/unified/ql/lib/unified.qll
+++ b/unified/ql/lib/unified.qll
@@ -1,3 +1,7 @@
+/**
+ * Provides classes for working with the AST, as well as files and locations.
+ */
+
 import codeql.Locations
 import codeql.files.FileSystem
 import codeql.unified.Ast::Unified