Your debit card is tied to your Fidelity Cash Management account where you have a positive balance, enough for your upcoming trip's need, of course. You can use the debit card for ATM withdrawal, or you can do Cash Advance at local bank, to get the local currency for the cash usage in your trip.
Yes, the local bank transaction is in Local Currency - it then charge (debit) your Fidelity Cash Management for the equivalent amount in USD, at the Visa determined exchange rate (the same rate used for Credit Card transaction).
You can check both Visa and MC exchange rates here.
https://usa.visa.com/support/consumer/travel-support/exchange-rate-calculator.html
https://www.mastercard.us/en-us/personal/get-support/convert-currency.html
For checking the rates on your card versus the Mean market rate (usually Very Close)
实际上,当您使用 Google 搜索时,您可以使用很多网站。
但是我习惯用了很多年了的XE.com。
https://www.xe.com/currencytables/
https://www.oanda.com/fx-for-business/historical-rates