Calcula o tempo total de uma playlist no Youtube. É só colar no console na página da playlist. Update para a nova interface do Youtube

playlist_time.js

(function () {
  const timeContainer = document.querySelectorAll(
    ".ytd-thumbnail-overlay-time-status-renderer"
  );
  let timeSeconds = 0;

  for (let i = 0; i < timeContainer.length; i++) {
    const timeStr = timeContainer[i].innerText;
    if (!/\d?\d:\d{2}(:\d{2})?/g.test(timeStr)) continue;
    const timeParts = timeStr.split(":");
    let seconds;

    if (timeParts.length === 3) {
      seconds =
        parseInt(timeParts[0]) * 60 * 60 +
        parseInt(timeParts[1]) * 60 +
        parseInt(timeParts[2]);
    } else {
      seconds = parseInt(timeParts[0]) * 60 + parseInt(timeParts[1]);
    }
    timeSeconds += seconds;
  }
  const renderNumber = (number) =>
    number <= 9 ? `0${Math.round(number)}` : Math.round(number);

  console.log(timeSeconds);

  const hours = timeSeconds >= 60 * 60 ? timeSeconds / 60 / 60 : 0;
  const minutes = timeSeconds >= 60 ? (timeSeconds / 60) % 60 : 0;
  const seconds = timeSeconds % 60;
  const result = `${renderNumber(hours)}:${renderNumber(
    minutes
  )}:${renderNumber(seconds)}`;

  alert(result);
})();

Atualizado novamente!