The code is the PlayStation "Title ID" used to identify the specific software build for the Asian region . Unlike North American or European versions, this specific ID is tailored for markets like Singapore, Hong Kong, and Taiwan.
To understand why you might choose V1.33.AS.ZH.CN-CUSA00912 over other releases, see the table below: Uncharted4 A Thiefs End V1.33.AS.ZH.CN-CUSA00912