HTML in footer turns textual and throws error

I am now studying Print Formats of introduction to ERPNext here

At 2:12, I tried adding footer html as shown in video,


But once saved and when I am back to edit and change, it turned out with symbols replaced by text. For ex, < became &lt;.

&lt;div class=&quot;text-center&quot; style=&quot;&quot;&gt;
    &lt;div style=&quot;font-weight: bold; font-size: 16px;&quot;&gt; XXX YYY XXXXX&lt;/div&gt;
    &lt;div&gt; 3/293, doignoasidgn osadignaso di oasndginao goasdino&lt;/div&gt;

Why does this happen? Is there a quick way to revert? Because it does not work, and throws error if I save again in this format itself.

For now painstakingly I am replacing with this multiple find&replace tool to get back original html format.