The data in this directory consists of real certificates issued by Let's Encrypt in 2023. The ones under the bad directory were issued during the Duplicate Serial Numbers incident (https://bugzilla.mozilla.org/show_bug.cgi?id=1838667) and differ in the presence / absence of a second policyIdentifier in the Certificate Policies extension.

The ones under the good directory were issued shortly after recovery from the incident and represent a correct correspondence relationship.