Leo's talk, Verified Collaboration, presented as part of the Simon's Foundation Presidential Lecture series on mathematics and computer science has recently been posted.
Watch it here: https://www.youtube.com/watch?v=rmMYFmlUbJ8
There are some great examples of cross-disciplinary collaborative efforts highlighted, including the Liquid Tensor Experiment and SampCert, which Leo notes would have been impossible with the strength of Mathlib and the #LeanProver community behind it.