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 playlist = document.querySelector("ytd-playlist-video-list-renderer");
const timesContainer = playlist.querySelectorAll("ytd-thumbnail-overlay-time-status-renderer");
let timeSeconds = 0;

for(let i = 0; i < timesContainer.length; i++){
    const timeStr = timesContainer[i].querySelector('span.style-scope').innerHTML;
    const timeParts = timeStr.split(":");
	const seconds = (timeParts[0] * 60) + parseInt(timeParts[1]);
    
    timeSeconds += seconds;
}

const hours = (timeSeconds / 60) / 60;
const minutes = (timeSeconds / 60) % 60;
const seconds = (timeSeconds % 60);
const result = parseInt(hours) + ":" + parseInt(minutes) + ":" + parseInt(seconds);

alert(result);

})();

Vlw Rafa, vou atualizar o original....