VST PlugIns.
VST PlugIn Format Technology was developed by Steinberg Soft-und Hardware GmbH.
VST Plugins need to be installed into this folder in order to make them available for use in Vision DSP. 

Some VST plug-in installers may specify that you find the same named folder but for Cubase. It is likely that these plug-in manufacturers have not updated their installers to include Vision. If you are presented with such a message simply locate this folder and install the plug-in into it.

Technical support for individual plug-ins is supplied by the Plug-in manufacturer. 

Opcode Team