Clojurians Log v2

Question about the component library. Where can I find documentation about the metadata approach. The readme mentions it in passing. About storing the metadata on each component. Do I still need to define a record for each component? I've found code like https://github.com/seancorfield/next-jdbc/blob/bb8b0c4efd38ac2dc466b9e9ac64109e0b1df5fe/src/next/jdbc/connection.clj#L323-L333