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.

Managed App Accounts Tab