tests/core/go_proto_library/no_go_package.proto - third_party/github.com/bazelbuild/rules_go - Git at Google

 syntax = "proto3";

 package protopkg;

 message Foo {
   int64 x = 1;
 }
	syntax = "proto3";

	package protopkg;

	message Foo {
	int64 x = 1;
	}