Include config option within ssh_config command output template. Default remote_user value to set username value. Include existence check on provided config value to ensure file is available. Update tests to include coverage on all changes. Add new options to the docs.
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.