What is the manual exchange rate in Xero?

What is the manual exchange rate in Xero?

Organisations with multiple currencies struggle to provide the required exchange rates for specific requests: currently all requests are created with the current rate, which works fine for today's and future dates but fails to meet the expected values of past requests.

To resolve this issue, a feature for specifying an exchange rate for particular dates was introduced.
For requests created not in the base currency, ApprovalMax now allows to set the exchange rate manually: