How does the «Authorize.Net» payment extension send the customers bank card details to the Authorize.Net server?

When I test it though, it isn’t making a request to Authorize.Net’s servers, either. The CC data simply isn’t being sent anywhere, as far as I can tell.

The «Authorize.Net» payment module sends the bank card data to the Authorize.Net server here:

Here is a detailed explanation of the Authorize.Net’s Direct Post method:
https://community.developer.authorize.net/t5/The-Authorize-Net-Developer-Blog/Direct-Post-Method-DPM/ba-p/7014