Package bitwarden is used for managing the ciphers, encrypted on the client side.

Package contact is for managing the io.cozy.contacts documents and their groups.

Package instance is for the instance model, with domain, locale, settings, etc.

Package job is for the scheduling and execution of asynchronous jobs via the workers.

Package nextcloud is a client library for NextCloud.

Package note is the glue between the prosemirror models, the VFS, redis, the hub for realtime, etc.

Package oauth declares the OAuth client, and things related to them, from the certification of the flagship app to the creation of the access codes in the OAuth2 flow.

Package office is for interactions with an OnlyOffice server to allow users to view/edit their office documents online.

Package permission is used to store the permissions for each webapp, konnector, sharing, etc.

Package sharing is where all the magic happen when documents/files are shared between several Cozy instances, from managing the recipients to replicating the changes.

Package vfs is for storing files on the cozy, including binary ones like photos and movies.