Final answer:
A user holding the 'sn_customerservice.partner' role in a CSM application is called a partner user and operates in a Business-to-Business (B2B) context, managing cases and viewing assets for their own and partner accounts.
Step-by-step explanation:
The user with the role sn_customerservice.partner is typically known as a partner user in the context of Customer Service Management (CSM) applications. Given their abilities to create, view, and edit cases for their account and their partner account, as well as viewing assets owned by these accounts, this user functions within a Business-to-Business (B2B) context rather than Business-to-Consumer (B2C). The B2B designation reflects the nature of interactions between two businesses, whereas B2C involves direct transactions between a business and an end consumer.