diff --git a/envoy/config/core/v3/config_source.proto b/envoy/config/core/v3/config_source.proto
index 3277fdf2..d7b68a9a 100644
--- a/envoy/config/core/v3/config_source.proto
+++ b/envoy/config/core/v3/config_source.proto
@@ -285,3 +285,11 @@ message ExtensionConfigSource {
 // A placeholder proto for the registration for the REST subscription implementation.
 message RestSubscription {
 }
+
+// A placeholder proto for the registration for the filesystem subscription implementation.
+message FilesystemSubscription {
+}
+
+// A placeholder proto for the registration for the filesystem collection subscription implementation.
+message FilesystemCollectionSubscription {
+}