how_much_netflix.js

// how_much_netflix.js
// A script that looks through your Netflix viewing activity and
// tallys up how much time you've spent watching Netflix
//
// INSTRUCTIONS TO USE:
// Open https://www.netflix.com/WiViewingActivity and the developer console
// Copy and paste this script into the developer console and press enter
//
(function() {
  var fetchAllViewedItems = function() {
    var deferred = jQuery.Deferred();
    var viewedItems = [];
    (function fetchPage(page) {
      jQuery.getJSON('https://www.netflix.com/api/shakti/b6260b85/viewingactivity?pg=' + page).done(function(json) {
        viewedItems = viewedItems.concat(json.viewedItems);
        console.log('Fetched %s viewed items', viewedItems.length);
        if (json.viewedItems.length == json.size) {
          fetchPage(++page);
        } else {
          deferred.resolve(viewedItems);
        }
      }).fail(deferred.reject);
    })(0);
    return deferred.promise();
  };
  fetchAllViewedItems().then(function(viewedItems) {
    var totalTime = viewedItems.reduce(function(runningTotal, viewedItem) {
      return runningTotal + viewedItem.bookmark;
    }, 0);
    var days = Math.floor(totalTime / 60 / 60 / 24);
    var hours = Math.floor((totalTime / 60 / 60) % 24);
    var minutes = Math.round((totalTime / 60) % 60);
    console.log('According to your viewing history, you have cumulatively watched %i days, %i hours and %i minutes of Netflix', days, hours, minutes);
  });
})();

That always changing number is build identifier for Netflix API, it probably changes with every new build of their API. You can find current one in source of the page, search for BUILD_IDENTIFIER.