Trigger a community builder user subscription/sign-in with a script

Thank you Krileon we've just tried the Email action on onAfterUserConfirm trigger and it successfully sent an e-mail to the correct recipient.
Now the e-mail we want to send is completely customized and includes HTTPS links stored on the server depending on the user's data.
How to fetch these custom data in the generated e-mail?

The user object for that trigger should default to the user being confirmed. So you should be able to just use normal substitutions to get their profile data (e.g. [username]).