The short answer is, …“none”. The Bigfix team doesn’t publish any fixlets based on the Spacewalk repositories, they publish fixlets for the vendors’ official repos.
Now, those fixlets may happen to work with those repos, if you’ve configured either the custom repository option or updated the CentosR2Plugin on the server to reference those repos.
When using custom repos or the plugin, you could use the “run yum command” task to do something like
yum update if you just want to upgrade all packages to the latest.
Edit: thanks, Matt, I was just looking for that link