As of `net-ssh` version 4.2.0, the key :paranoid has been deprecated in favor of using :verify_host_key. This commit updates Vagrants ssh config to use the new key, and deprecates the use of :paranoid.
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.