The License node contains information about the license applied to this solution. From the action menu you can refresh or install a license.
SKU's
A SKU is defined by ProductId + VariantId. Language is disregarded. So, one master product with four variants will count as a SKU count of 5.
Email recpients
An email recipient is defined as a an active default user (UserType = 5) with the "Email allowed" checkbox checked (true).