Depends on your definition of “what”, and the server you’re talking to, and what DNS you’re using, and your VPN provider, and maybe the phase of the moon.
So, pretty much the best-case scenario is when the site works via https, and the server supports “encrypted client hello” (ech), and your browser has ech enabled. In this case your VPN provider can see that you’ve sent something to the IP (one IP can host multiple websites with different domains).
Https and no ech = can see IP, can see the domain.
Http = can see everything (thankfully, quite rare now).
Some VPN providers may as well use their own DNS, then they can see what domains you’ve talked to regardless of ech (afaik, since domain lookup should happen before client hello, since you’re basically looking up whom to “greet”)
Some providers are Facebook with fake mustache and will shamelessly try to mitm you
May I interest you in using
unwrap_or
instead ofunwrap