This commit includes all detailed disk information from VirtualBox inside its storage structure in Vagrant. This gives Vagrant more detailed access for a disk beyond its uuid and port/device such as its capacity and the type of disk it's classified as.
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.