Press the "Fetch" button and see the result under the "Result" label.
Clicking the button will fetch the first 128 bytes from raw.githubusercontent.com/OpenXcom/OpenXcom/bin/common/SoldierName/Danish.nam, or in the case of Firefox 99.0b8 (64-bit), throw an error.
Use DevTools to see more network information.
Test-case source Fetch API Documentation CORS-safelisted request-header documentation