Hello, I am the Bootkitty developer. The reason our bootkit is self-signed is because it uses the LogoFAIL vulnerability to register a MOK on the system to bypass secureboot, which is why our signature is included. I will leave an analysis article about LogoFAIL at the link below.
https://www.binarly.io/blog/logofail-exploited-to-deploy-boo...