With(See T119158 and T73394) this will no longer really be an issue once that patch is deployed, but given all the trouble with lang converter, might make sense as a hardening step.
<div id=".3Efoo"></div> <h2> <span class="mw-headline" id=">foo">>foo</span><span class="mw-editsection"> <span class="mw-editsection-bracket">[</span><a href="/w/git/index.php?title=Special:ExpandTemplates&action=edit&section=1" title="Edit section: >foo">edit</a> <span class="mw-editsection-bracket">]</span></span> </h2>
Note in particular: <span class="mw-headline" id=">foo">
Making that > be > might be better as a hardening step against lang converter (or anything that uses regexes in a similar manner) mucking about.
As an aside, this issue was noticed with the help of afl
Backports:(Master as of last July 2016)