I remember seeing the app on my TS-233, but never went to use it till tonight. I cannot install it nor find it even on Qnap’s website. Is it no longer available for this model?
Virtualization Station was never available for the TS-233. It’s for x86 CPUs only.
You may have seen Container Station, which is still available.
Also, I now recall there’s a shortcut placed on the default QTS desktop (on compatible models) which is a virtualisation guide. That also may have been what you saw.