According to Variety:
Among the topics brought up by Maron: fame, meeting fans, recording with John Lennon and the long life of the Beach Boys vs. Beatles oneupmanship as well as the Beatles vs. Rolling Stones rivalry. Of the latter, said McCartney: “We were at that Oldchella thing together. They’re great. We go back a long way and there was never really a rivalry.”
Asked about “Helter Skelter,” McCartney recalled being “suddenly singled out for being the soundtrack to a murderer. … For years I wouldn’t do that song. I felt like if I did it, it would be a victory for him. Then I thought, ‘Wait a minute, I wrote it!'”
The interview with Paul isn't listed, yet, but you can download "WTF" episodes here.