13.10.9 The “--valid-syntax” and “--no-valid-syntax” Query Flags
Over time, the syntax of database objects changes. The existing data is not always updated when these changes occur. Therefore, there are many objects in the RIPE Database with invalid syntax according to current rules. These query flags filter the objects in the query response. Either those objects with valid syntax, or those without valid syntax, will be returned in the response depending on the choice of flag.