ERC-20 approvals are public authorization records that can reveal which wallet allowed which spender contract to use a token and for what allowance.
Approval before transferFrom
Many swaps require an approval so a router can move tokens. The approval and later token transfer are separate observable events.
Allowances reveal application history
Known spender contracts can indicate which applications a wallet prepared to use even if the later swap failed or never occurred.
Revocation has a limited role
Reducing an allowance can improve future security but does not delete the historical approval transaction.
Private Route boundary
A privacy-focused delivery cannot hide the Ethereum approval submitted by the source account. Users should review both privacy and token authority.
How to read the evidence
Ethereum evidence is account- and execution-oriented. Review the externally owned account, nonce, gas payer, transaction target, calldata, receipt, logs, token approvals, and internal effects. Verified contract interfaces can make an interaction easy to interpret, but raw records remain when labels are absent. Reusing the same EVM key across networks can also make cross-network research simpler.