Email Designer Tagging

I know ACS Email Designer uses specific tagging.  Is there some documentation on the ACS Email Designer HTML Tagging.  Sample below...  

<div class="acr-container">
<div class="acr-structure" data-structure-id="1-1-column" data-structure-name="richtext.structure_1_1_column">
<table class="structure__table" align="center" cellpadding="0" cellspacing="0" border="0" width="750">
<tbody>
<tr>
<th class="colspan1" data-name="Drag a new component here.">
<div class="image-container acr-fragment acr-component" data-component-id="image" style="width: 100%; text-align: center;" data-component-name="richtext.component_image" data-thumbnail="" contenteditable="false">
<!--[if mso]><table cellpadding="0" cellspacing="0" border="0" width="100%"><tr><td style="text-align: center;"><![endif]-->
<img src="https://" width="750" style="width: 100%;" height="0" title="" alt="" align="">
<!--[if mso]></td></tr></table><![endif]-->
</div>

For example "div class="acr-container", "div class="image-container acr-fragment acr-component"?  Are the ACS classes listed in some documentation somewhere so we can code emails responsively using the email designer components?  Want to make sure when we write the HTML and open Email Designer, it is using the components and it is easily editable...