This is a small, bare-bones IRC client.
It's marginally usable in itself with a readline-like user interface.
If it is started with the -sub flag it can be used to create the core of an IRC client with a richer user interfaces in front of it, connected to stdout and stdin.
To connect to a server, use
/tlsconnect server:port nick
or /connect for unencrypted connections.
There is a sample configuration file with comments in
mub.yaml.sample.