Well, it’s not exactly Obi Wan telling Luke what happened per say…
It’s more like Obi Wan is answering Luke’s questions about his father and then when he asks “how did my father die?” we then see Obi Wan kind of freeze on that question and then flash to the Star Wars logo and opening crawl. We’d be coming back to Obi Wan once Vader’s helmet is lowered onto Anakin and we hear the iconic breath a few times. Then Obi Wan says how Vader betrayed and murdered Luke’s father. This also helps line up what Obi Wan says in ROTJ that it’s true from a certain point of view (still a dick move, but it aligns things properly). I’m not sure yet, but we will jump back one last time for the ending from older Obi Wan to the conversation between Yoda, Bale and Obi Wan about going into hiding and we will end not on the binary sunset shot, but on Obi Wan looking at the Lars’ as they are holding Luke.