test/VCM/v18.xml - third_party/libxml2 - Git at Google

 <!DOCTYPE doc [
 <!ELEMENT doc (a? | b?) >
 <!ELEMENT a EMPTY>
 <!ELEMENT b EMPTY>
 <!ELEMENT c EMPTY>
 ]>
 <doc><b/></doc>
	<!DOCTYPE doc [
	<!ELEMENT doc (a? \| b?) >
	<!ELEMENT a EMPTY>
	<!ELEMENT b EMPTY>
	<!ELEMENT c EMPTY>
	]>
	<doc><b/></doc>