The response is a User, documented under Shared objects. It is the same information signing in returns in user_info, so the app can refresh its view of the account without signing out and back in. That matters right after GET /api/v1/accept-invite, where the newly joined workspace is missing from the token holder's cached memberships until something re-reads them.

The call takes no parameters and always describes the bearer token's own account. To read the other members of a workspace, use GET /api/v1/get-users-from-workspace instead.