Question

I remember reading something about it a few years back but I don’t remember anymore.

Was it something to do with IE and parsing it as plain text…?

Answer 1

I think you mean CDATA

source

This fixes the validator. The problem is that some older web browsers
don’t understand the CDATA tag and so this breaks your Javascript in
those web browsers. Fortunately, Javascript multi-line comments start
and finish with characters that do not cause validation errors. We can
therefore comment out the CDATA tag in so far as the Javascript
processors within the web browsers are concerned while still leaving
the Javascript content defined as CDATA as far as the validator is
concerned. We do it like this:

<script type="text/javascript">
/* <![CDATA[ */
// content of your Javascript goes here
/* ]]> */
</script>