We don't know. Soon... maybe.
Where are the russian hackers when you need them?

Prospero is one of Valve's first games to be ever developed. It was cancelled so that the developers could get focused on developing Quiver (codename for Half-Life)
To this day, only a handful of screenshots, some concept art and a single texture have seen the light of the day...
More info on Prospero

It would be interesting to see how does one of the first Valve games looked and played like. Also, it is the beta of betas, the cancelled game of the cut contents.
Also, its a beytah!11!!! (maybe dark and gritty?!?!?)

Yes. No. Maybe. I don't know.
On one side, it would be cool if you could get your hands on the files. On the other side, hacking into Valve's servers and stealing data is probably a little bit illegal.
If you can post the files before getting caught by the FBI... i'm not encouraging it, but if you manage to do so...