Mercurial represents history as a DAG. You can implicitly create unnamed branches and explicitly create named branches. Committing to a named branch records the

Mercurial represents history as a DAG. You can implicitly create unnamed branches and explicitly create named branches. Committing to a named branch records the branch name as part of the changeset. Extensions are just how Mercurial commands are implemented. The extensions for editing history are included and supported. The default configuration is just very conservative.