This is simply implementing support for IRCv3 nested batches. Its utility is dependent on the type of information that the server wants to provide. There is no difference between a batched event and a normal event. The only difference is that the server is telling the client not to process the batched events until end of batch is received. Once that is received, all the cached lines are processed as normal events.
I have provided the above example /parselines to allow beta-testers to test out the nested batch parsing to make sure it is working correctly.