[dgreisen]

There are a number of technical limitations to gpg signatures. Your hypothetical attacker who has access to github can simply add his/her key and show up as a verified committer. gpg signatures have many other issues including metadata corruption, not to mention the nearly insurmountable issues around key management. As mentioned below, we have internal systems that allow us to audit/authenticate the repository. We will be rolling out a UELMA-compliant authentication scheme based on TUF in the next several months that will allow the public to authenticate the repository.