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<title>Custom Elements: the HTML fragment parsing algorithm must not create a custom element synchronously</title>
<meta name="author" title="Rob Buis" href="mailto:rbuis@igalia.com">
<meta name="assert" content="The HTML fragment parsing algorithm must enqueue a custom element upgrade reaction instead of synchronously invoking its constructor">
<link rel="help" href="https://html.spec.whatwg.org/multipage/parsing.html#create-an-element-for-the-token">
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