Internal changes.

PiperOrigin-RevId: 625437318

src/google/protobuf/compiler/php/php_generator.cc

@@ -1067,6 +1067,9 @@ void GenerateHead(const FileDescriptor* file, io::Printer* printer) {
   printer->Print(
       "<?php\n"
       "# Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
+      "# NO CHECKED-IN"
+      // Intentional line breaker.
+      " PROTOBUF GENCODE\n"
       "# source: ^filename^\n"
       "\n",
       "filename", file->name());