Hi,
We found that 'https://api.box.com/2.0/shared_items' (Find item for shared link) API endpoint supports 'fields' param in requests, but it is not documented here - https://developer.box.com/en/reference/get-shared-items/#request. It works in the same manner as 'fields' param for 'https://api.box.com/2.0/files/:file_id' (Get file information) endpoint.
Could we relay on this field in the production code?