Many wallet applications create automatic backups. For example, Dash Core automatically creates a copy of the wallet.dat in the dashcore/backups folder each time it opens. By default, up to 10 backups are stored, with the oldest being deleted when new ones are created.
These actions force your wallet software to read through the blockchain ledger, find all the transactions associated with your private keys, and calculate your correct balance. Whether you're a casual user restoring an old wallet or a developer building a blockchain explorer, the principle is the same: keeping a wallet's index synchronized with the blockchain is an essential and routine task in the world of digital currencies.
indexof is a Google search operator that reveals directory listings on poorly configured web servers. A search like indexof: wallet.dat is sometimes used by people hoping to find exposed wallet files online.
While encrypting your wallet.dat with AES-256-CBC protects your private keys, . If you're concerned about others seeing your financial activity, consider encrypting the entire file with an additional tool like GPG.