Guides
COM — composite component
For composite works (medleys and the like): one line per component work, with its title, writers, and identifiers.
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 COM 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.