Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
HTML issues tagged as unescaped.
The < and > characters are reserved for HTML tags, so if you need to use them as content, they should be escaped as < and > respectively.
For example, to illustrate the mathematical truth that 1 < 2 in HTML, we can write it this way:
<p>1 < 2</p>
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