XXX_* type in generated *.pb.go file

If you want to specifically exclude them when generating, you can add this to your file

import "github.com/gogo/protobuf/gogoproto/gogo.proto";
option (gogoproto.goproto_unkeyed_all) = false;
option (gogoproto.goproto_unrecognized_all) = false;
option (gogoproto.goproto_sizecache_all) = false;

edit: Styling

The XXX_ types are used by the Protobuf library to store unknown fields. When you decode a proto, there may be additional fields in the serialized data that the library doesn't know what to do with. This can happen, for instance, when the reader and writer of the data are using different copies of the proto file. This is a feature to help with backwards compatibility between clients and serves built at different times.

Additionally, the XXX fields allow you to expose extensions, which were part of Proto2. They were removed in Proto3 in favor of Any, but the library still needs to support them.

As for what you should do with these? I would just leave them alone, and don't reference them. You don't need to set them, and you don't need to read them. The Go protobuf library will handle them for you.