nondeterministic wallets each change address is randomly generated out of nothing, HD means they are derived from a seed in a way that can be easily recovered if you have the seed

nondeterministic wallets you MUST back up the file, and every new address on it is missing from earlier backups compared to new ones

these are UTXOs private keys

i'm pretty sure i have got them on the disks i just wiped the partitioning information, repartitioned, so that part of the disk is mangled but it's at the front of the disk, the rest should be pretty much intact