Vocaloid 2 Yuki by AH Software is a Virtual Instrument Audio Plugin and a Standalone Application for macOS and Windows. It includes, and is therefore "powered by", Vocaloid, which functions as a VST Plugin, an Audio Units Plugin and a Standalone Application. It supports ReWire.
The OS and Format icons below are for the latest version of Vocaloid. The version numbers are for Vocaloid 2 Yuki.