%om.RO

om.RO (omissibility indicator (XML version)) A dummy component of an XML element declaration, retained for SGML compatibility.
Note

Omissibility is not allowed for XML element declarations. This parameter entity therefore has a non-null value only when an SGML DTD is requested.

Declaration <!ENTITY % om.RO '' >
See further 3.8.4 Generation of an XML DTD