According to the HTML5 spec, normal elements must have a start and end tag, but for some exceptions. Currently Parsoid accepts these tags as valid, as seen in the test: "Handling html with a div self-closing tag" in parserTests.txt:
<div title /> <div title/> <div title/ > <div title=bar /> <div title=bar/> <div title=bar/ >
results in
<div title="" data-parsoid='{"stx":"html","selfClose":true}'></div> <div title="" data-parsoid='{"stx":"html","selfClose":true}'></div> <div title="" data-parsoid='{"stx":"html","selfClose":true,"brokenHTMLTag":true}'></div> <div title="bar" data-parsoid='{"stx":"html","selfClose":true}'></div> <div title="bar" data-parsoid='{"stx":"html","selfClose":true}'></div> <div title="bar/" data-parsoid='{"stx":"html","autoInsertedEnd":true}'></div>
PHP parser renders them as text:
<p><div title /> <div title/> </p> <div> <p><div title=bar /> <div title=bar/> </p> <div title="bar/"></div> </div>