I learned about this in Universal Studios.  I never even knew this existed (I'll bet it's on that Special Edition ET DVD I never opened).   This is the complete lost scene of Harrison Ford in ET, he is not seen in the movie because Spielberg didn't want to show the adults (except for Elliot's mother and the government guys).  In some ways this scene works better and is more parallel with the beginning of the film where Elliot was mistreated by his brother and friends and this ending shows him being included with them and that life has gone pretty much back to normal for him because of his experiences with E.T.