Parsing InvalidWitnessesUTXOW error message

I’ve been working on updating the registration for an already-registered pool. This pool’s pledge is secured by a hardware wallet and thus requires multiple witnesses.

When attempting to update the registration, I’m encountering this error:

$ cardano-cli transaction submit     --tx-file tx-pool.multisign     --mainnet
Command failed: transaction submit  Error: Error while submitting tx: ShelleyTxValidationError ShelleyBasedEraMary (App
lyTxError [UtxowFailure (InvalidWitnessesUTXOW [VKey (VerKeyEd25519DSIGN (PublicKey "e!) \247^PS4\235\163\166\\`\184\20
0\217\&0/i\248u\223\226\175\227\155\236\199\233_\204"))])])

What is the number string included in that error message? Does it string refer to a specific vkey? This:

\247^PS4\235\163\166\\`\184\200\217\&0/i\248u\223\226\175\227\155\236\199\233_\204

Can I decode that string somehow to figure out which key is giving me problems?