csharp/protos/extensions/extensions_a.proto

syntax = "proto3";

option csharp_namespace = "Google.Protobuf.TestProtos.Extensions";

// This file is used as part of a unit test for issue 6936
// We don't need to use it, we just have to import it in both b and c

import "google/protobuf/descriptor.proto";

extend google.protobuf.MessageOptions {
    string opt = 50000;
}