This directory contains the in development definition of the Chrome Root Store. It is currently not used for trust decisions in Chrome.
The root store is defined by store/root_store.textproto file, which is a RootStore protobuf message, defined in //net/tools/root_store_tool/root_store.proto. It references certificates in the store/certs directory. The root_store_tool will files in this directory to eventually use this data for trust decisions in Chrome.