The answer
Usually not the secret, but the plate model can reveal your backup format; images of filled plates are dangerous.
What to do next
Do not photograph completed backup plates or put recovery material in cloud photo libraries.
Trezor hardware wallets
Hardware wallet or backup product relevant to a self-custody question. Availability, supported assets and local eligibility must be checked before signing up or buying.
Visit Trezor hardware wallets ↗Official provider link · Compare suitability and availability before choosing.