XML import chokes on % sign in link references

Running Filter Streams halts on errors shown at https://forum.xwiki.org/t/how-do-i-find-the-illegal-hex-character-that-halted-a-mediawiki-xml-conversion-through-filter-streams which happen just if the initial line from MediaWiki's dumpBackup.php is not first removed from the XML file, that line being in my case:

<mediawiki xmlns="http://www.mediawiki.org/xml/export-0.10/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mediawiki.org/xml/export-0.10/ http://www.mediawiki.org/xml/export-0.10.xsd" version="0.10" xml:lang="en">

Attached file ("nx6") errors as is, succeeds when that first line is removed. A number of other pages similarly fail if in the context of that line's specs, but import cleanly after the line is removed from the XML file.