He’s talking about Andres Freund, who uncovered the OpenSSL backdoor that was slipped into liblzma from the xz malicious maintainer. Dude saw a valgrind error and a function with a fixed runtime was taking too long and using too much CPU and reversed out and saved a major ssh backdoor from going upstream as Fedora was going to release it just days later.
It’s still bonkers to me that Kazaa’s network still technically lives on in Skype, though all the Supernodes are in Azure these days rather than the original P2P setup.