This episode pays off an image that can be spotted in the original Tangled film's closing credits.
Vigor the Visionary was supposed to appear in the Tangled (2010) movie, where he would almost reveal to Rapunzel that she was the lost princess. This story exists in storyboard form, complete with voice acting, but it never actually made it to the film.
As of this episode, all the original voice stars of 'Tangled' have appeared in the series. Apart from Brad Garrett, they have all voiced the same characters.