Substitute Characters in Object Names and Literals Returned in an EXPLAIN Report
If an object name or literal returned in an EXPLAIN report includes a character not in the the session character set, or is otherwise unprintable, the name or literal is shown as a UNICODE delimited identifier or literal.
Each non-representable character is escaped to its hexadecimal equivalent.
The system uses BACKSLASH (U+005C), if available, as the escape character. If BACKSLASH is not available:
Object names that are translatable to the session character set, but are not lexically distinguishable as names are enclosed in double quotation marks.
For information on object naming, see SQL Fundamentals.