Using this installer, all Composer packages of "type" : "aura-package" will be installed under package/Vendor_Name.Package_Name (note the directory, capitalization, and punctuation). This is a layout specific to the Aura system.

Aura packages do not need to be installed in a particular location when used outside of an Aura system. If you install an aura-package without this installer, the package will be installed to the default Composer location of vendor/vendor_name/package_name. As such, if you are not building an Aura system, you probably don't need this installer.

Note that this is not an Aura package proper; it is designed for use directly with Composer, and as such will be placed in vendor not package.