Guides
ALT — alternate title
Additional titles the work is known by — translations, abbreviations, working titles — so societies can match usage reported under any of them.
The exact field layout — positions, sizes, and formats — is defined in CISAC's CWR specification (CWR19-1070R1), available to CISAC members and licensees. The validator implements the full layout: drop a file on it and every ALT line is parsed field by field, with problems tied to the exact characters at fault.
Check a CWR file free — errors and warnings tied to the exact line, nothing stored: cwrcheck.com.