https://gerrit.wikimedia.org/r/#/c/398616/9/tests/citeParserTests.txt
From
<span about="#mwt2" class="mw-ref" id="cite_ref-[#foo]_{bar}_<baz_1-0" rel="dc:references" typeof="mw:Extension/ref"
to
<sup about="#mwt2" class="mw-ref" id="cite_ref-[#foo]_{bar}_<baz_1-0" rel="dc:references" typeof="mw:Extension/ref"