When sending emails from/as someone else, do Google Apps Script quotas go against the user executing or the from/as user?

Question

I have my Gmail account configured to let me send emails as another Gmail account.

When I send emails from a GAS project on my account, but sending from/as the other account, whose quotas are used?

If I ([email protected]) run the following script, will it use my ([email protected]) quota or the quota of [email protected]?

function myFunction() {
  GmailApp.sendEmail("[email protected]", "test me", "test me", {
    "from": "[email protected]"
  });
}