Sort of like protobuf, but nothing like it at all at the same time.
Protobuf is a well thought out design and implemention. This is a quick hack just to prove that I could quickly define a message in a yaml format, and using a little python + Jinja2 templates to create a message definition and generate code that could serialize/deserialize messages with minimal effort.
Some minimal support handle network endianess. Not fully tested...
Look at the example file in msg/msg.yaml for an example file format.
Look in the test directory for test code and infrastructure to support serialization/deserialization.
YMMV...