Shared Contacts for Gmail is a Google marketplace application. For better security, it uses Google authentication system and will need to access your contacts in order to share them with your team. If you are a Google administrator installing the application for your domain, we also require permissions to access the users of your domain, in order to facilitate internal sharing, your domain groups (to be able to share automatically with all members of a group), your Google licenses (to be able to offer you bundles offers) and some security settings in order to give you an overview of the other permissions you granted to your domain.