How can I find out who signed the OS X app?

On Windows, I can right-click the file and see who signed it on the Digital Signatures tab of the Properties dialog box. Is there a similar way to see which publisher signed the OS X application, or information about the certificate used to sign it?

I know that I can run codesign -d -r- appname.appto find out the details of the certificate, and codesign -vvvv appname.appto find out if it passes the test, but none of them shows me anything about the actual certificate or the publisher that signed it, the package identifier for the application.