diff --git a/tools/gen/impl_template b/tools/gen/impl_template
index 353c5d551..341175bee 100644
--- a/tools/gen/impl_template
+++ b/tools/gen/impl_template
@@ -1,5 +1,5 @@
 /* This file was generated by generate-wire.py */
-/* Do not modify this file! Modify the _csv file it was generated from. */
+/* Do not modify this file! Modify the .csv file it was generated from. */
 /* Original template can be found at tools/gen/impl_template */
 
 #include <${header_filename}>
diff --git a/tools/gen/print_header_template b/tools/gen/print_header_template
index c82baafc0..dc01e9c47 100644
--- a/tools/gen/print_header_template
+++ b/tools/gen/print_header_template
@@ -1,5 +1,5 @@
 /* This file was generated by generate-wire.py */
-/* Do not modify this file! Modify the _csv file it was generated from. */
+/* Do not modify this file! Modify the .csv file it was generated from. */
 /* Template located at tools/gen/print_header_template */
 #ifndef LIGHTNING_${idem}
 #define LIGHTNING_${idem}
diff --git a/tools/gen/print_impl_template b/tools/gen/print_impl_template
index ec6cb8f55..b3f10c4f6 100644
--- a/tools/gen/print_impl_template
+++ b/tools/gen/print_impl_template
@@ -1,5 +1,5 @@
 /* This file was generated by generate-wire.py */
-/* Do not modify this file! Modify the _csv file it was generated from. */
+/* Do not modify this file! Modify the .csv file it was generated from. */
 
 #include "${options.header_filename}"
 #include <ccan/array_size/array_size.h>