Note: This calendar view maps the number of captures of https://accounts.google.com/ServiceLogin?ltmpl=mobile&service=youtube&uilel=3&passive=true&continue=https%3A%2F%2Fm.youtube.com%2Fsignin%3Faction_handle_signin%3Dtrue%26app%3Dm%26hl%3Den%26next%3D%252Fsignin_passive%26feature%3Dmobile_passive%26noapp%3D1&hl=en, not how many times the site was actually updated.
Look Up URL in general Internet Archive web collection.