diff --git a/src/google/protobuf/compiler/cpp/helpers.cc b/src/google/protobuf/compiler/cpp/helpers.cc
index fce4e80724..86d6196d01 100644
--- a/src/google/protobuf/compiler/cpp/helpers.cc
+++ b/src/google/protobuf/compiler/cpp/helpers.cc
@@ -1424,8 +1424,6 @@ bool GetBootstrapBasename(const Options& options, absl::string_view basename,
            "net/proto2/compiler/proto/plugin"},
           {"net/proto2/compiler/proto/profile",
            "net/proto2/compiler/proto/profile_bootstrap"},
-          {"third_party/protobuf/extension_declaration",
-           "third_party/protobuf/extension_declaration_bootstrap"},
       };
   auto iter = bootstrap_mapping->find(basename);
   if (iter == bootstrap_mapping->end()) {