Hello Marc,
CernerCare is an identity provider and is used by various applications.
While you do not need to be a customer of Cerner to login in to CernerCare, the permissions as to which resources/documents/wikis are accessible to you are determined on the level of access you have.
In general, to avoid adding a bunch of mappings that are only used once in the public sandbox, we typically only map a few of each "type" of mapping (i.e. wound on arm, COVID-19 result, blood pressure). If a use-case is encountered that can't be covered by existing mappings, we can help you find something similar to your exact needs.
Are you looking for any specific LOINC mappings?
Thanks,
Fenil