How do I find out who owns a specific apartment?

I recall about 15 years ago stumbling upon a website where I could just plug in our apartment building's parcel number and see a full list of every owner in the building.
I can't for the life of me remember which site it was, but I need those details for an apartment located in San Francisco.
Does anyone happen to know where I can find that?

That’s not quite right; it only shows me the building owner's name
The property is located at a building in San Francisco and is listed under parcel number 4201/8