6d4d9b9304
Prior to this commit, Vagrant would attempt to path expand a file that didn't exist if it was left out of the passed in arguments and no `--url` was used for external box uploading. This commit fixes that by adding some additional validation for the passed in box file.
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.