A plain comma-separated file, with one row per transaction and nothing proprietary about it — the format every spreadsheet and accounting tool will accept.
Useful when the destination is not Excel: an import template, a script, or a system that only takes CSV.
Date, description, amount and — where the statement prints one — the running balance, so the reconciliation you were shown is reproducible from the file itself.
Every conversion is reconciled before you see it: the running balance is checked row by row, or — when the statement never prints one — the opening balance plus every transaction is checked against the closing balance. If the statement gives us nothing to check against, we say so instead of showing a green tick.
The CSV is written locally from the result already returned, so the finished file never exists on a server.
Yes, when the statement prints one. When it does not, the reconciliation falls back to checking the totals.
Yes — a batch can be exported as a single CSV with a column naming the source statement.