If Google sells a part of its business to another company then the data required to operate that business must be included in the sale. That goes without saying

If Google sells a part of its business to another company then the data required to operate that business must be included in the sale. That goes without saying. And a lot of companies "sell user data" by that metric. Also, there is no indication that Squarespace has received any user data that is not required for them to take over Google Domain operations (so they would get a user's domains, billing info, etc but not their Google Maps location or their search history).