New CT log will not be trusted by Chrome and will provide a public record of certificates that are not accepted by the existing Google-operated logs. Submariner includes certificates chaining up to the set of root certificates Symantec recently announced it had discontinued, as well as a collection of additional roots suggested to us that are pending inclusion in Mozilla. The new log is accessible at Googleapis.com/submariner and is listed on our Known Logs page. We hope it will prove useful and help to improve web security.”]
Source: https://security.googleblog.com/2016/03/certificate-transparency-for-untrusted.html