Yes, and the pinned topic at the top of the index is the one I am referring to.
It's my way of writing
<div></div> in prose form. I've gotten into the habit of using the NODENAME for clarity. You'll also see
DIV-node in some of my answers of the past.
A division is a block level element that spans the full width of the screen and which may contain any element (except HTML, HEAD, & BODY) whether block level or inline. It's the most fundamental container in HTML.
In the above I suggested treating the marked LI as a DIV, meaning to consider it as the same type of container. It is, after all, a block level element with the same general properties as a DIV when we forego the default styles sheet, user style sheet and any properties inherited from UL or OL.
When creating a list within a list, the parent LI is just a container.
Your code does not have an OL, only a nested UL. It should conform to the instructions...
<li> <!-- treat this LI as a DIV -->
<h3>Things I Do in the Summer</h3>