The answer
A signature can sometimes authorise actions without an immediate on-chain transaction, while an allowance is a contract permission recorded on-chain.
What to do next
Read the exact signing request, spender and expiry; do not rely only on whether gas is charged.
Revoke.cash wallet permission scanner
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Trezor hardware wallet
Related self-custody hardware; verify supported coins, networks and recovery standards. It cannot reverse an already compromised seed or fraudulent transfer.
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