FWIW: I found an example in my test library. Starting out, the raw HTML for a comment is
Code:
<div>05/07/13<div>Dernière page lue : Emplacement 6514 (99%)</div></div>
Looking at the comment in Edit Metadata I see the text shown in this image:
Clicking the HTML source tab I see:
The source HTML is now transformed. <p> tags are added around the date and the nested <div> is changed to <p>.
The Normal view is now:
Adding a space after the date to force the comment to be saved, the raw HTML becomes
Code:
<div>\n<p>05/07/13 </p>\n<p>Dernière page lue : Emplacement 6514 (99%)</p></div>
It seems like the transformation also includes pretty-printing the HTML.