The signed list and the header check.
TorZon prints its own address in the page header and signs its mirror list, giving you two ways to confirm a genuine node.
The page header reprints the onion you should be on, so you can cross-check the address in your bar against what the market says its own address is. Do this before entering a password. A clone struggles to fake the correct address in the header while pointing you at the wrong one.
TorZon runs seven v3 onions concurrently, the deepest pool of any market on this catalog, and signs the set with a PGP key. Verifying the signature proves an address came from the market. The seven addresses on this page are checked against that signed list, so you always have somewhere to rotate.