[Doitsu]

@odedta: For all intents and purposes Kindle FXL books are like .pdf files, because all line-breaks need to be hard-coded. For example, the HTML code of the first paragraph looks like this:

<div class="txt fs1-txt2">
	<a class="app-amzn-magnify" 
		data-app-amzn-magnify='{"targetId":"fs1-txt2-magTarget", "sourceId":"fs1-2-txt", "ordinal":1}'>
		<div id="fs1-2-txt">
			<div class="dropcap">A</div>
			<div class="stanza">stands for APE, who has four clever <br/>
				&nbsp;&nbsp;&nbsp; hands:<br/>
				He lives in great woods in the<br/>
				&nbsp;&nbsp;&nbsp; tropical lands.</div>
			<div class="clear"></div>
		</div>
	</a>
</div>

If you open the example book with a Kindle app or Kindle Fire, you'll notice that you can't change the font size.
Also note the non-standard data-app-amzn-magnify attribute that is required for region magnification.