The accounts tab on managed-app (VIEW mode) shows related entities:
User Account: The user account - Each managed app is related with user account that is used for login into Content Glass and is also set with the special role: managed-app-client. he user account uses the website domain as a name and use Email provided upon on-boarding. For example, In the case of Shopify this will be the Email of the store.
Developer Accounts: The developer account assigned to the application - Each managed app is assigned wth developer account that holds the API-Key for accessing Content Glass API by CG apps running on the related website. Developer app entity is configurable and will be explained by "Developers Guide User Manual" doc.