Off Topic: But out of curiosity what does a Tor hidden service keep in memory? Would there be any information that would uniquely identify the services it's run

Off Topic: But out of curiosity what does a Tor hidden service keep in memory? Would there be any information that would uniquely identify the services it's running? Given that they're often run in datacentres (either colocated or within a VM) - wouldn't a USB device capable of scraping RAM and dumping a list hosted .onions be quite practical for law enforcement purposes? They're obviously finite amount of datacenters in each country/jurisdiction that accept bitcoin or sell VPSs.