I found this a while back, and it blew my mind.
It's a deleted scene with Biggs; it adds all the backstory about Biggs, who shows up in the last 30 minutes of the film and we have no idea who he is. It also adds a lot of character development for Luke; it explains almost everything about him, from clarifying what a hotshot pilot he is, slightly reckless, his feelings on the Empire. It also shows him as slightly immature, which since this is a coming of age story for Luke, really helps with the character development.
Why were these removed, and why were they subsequently ignored? It seems like they add a lot to the story.