Information that enables you to access the coins that are in the blockchain.

So each coin always remains in an address on the blockchain - that means NONE of your cryptoassets is in your hard/soft wallet or in your exchange account.

The main point, you do not know on what address on blockchain are your coins, there are simply too many possibilities to guess the address.

So many, so much so that it is more likely that all of your electrons in your body are doing quantum tunneling, and you go through a wall and get out on the other side without ever touching the wall, then you finding an address on a blockchain by a chance.