getting active user name in Google sheets from external domain - google-apps-script

Question

I have a published web app:
function doGet(request) {
// DocumentApp.getActiveDocument();
SpreadsheetApp.getActive();
var about = Drive.About.get();
var user = about.name;
// Logger.log(Session.getActiveUser().getEmail());
return ContentService.createTextOutput(user);
}
... at this URL:
https://script.google.com/macros/s/AKfycbzTlhKJXrTAEPEba0l1KWqqzlkul2ntC-0iHi7_POj0wk7j3R6K/exec
Which produces the desired result the user's full name (after authorization to user's data is approved - subsequent running of the URL does not prompt for authentication or approval)
That is the data I want to retrieve from this App Script:
function Test3() {
var options = {
'method' : 'get',
'followRedirects' : true,
// 'validateHttpsCertificates' : 'true',
'muteHttpExceptions' : true,
'contentType' : 'null'
};
var url = "https://script.google.com/macros/s/AKfycbzTlhKJXrTAEPEba0l1KWqqzlkul2ntC-0iHi7_POj0wk7j3R6K/exec"
var response = UrlFetchApp.fetch(url, options);
// var response = test2() ;
// var myName = response.getContentText();
Browser.msgBox("[" + response + "]");
}
but I have not been able to get just that data. Instead I get an a page HTML text, which equates to a Google login page.
Again, just running the URL manually from a browser as any user results in the user name web page, so why when run from app script, it can't just retrieve the result of that page?
What am I missing? Surely I'm some simple syntax away from getting that data.