Up until recently I've believed that for
text-overflow: ellipsis to work the element needs a set
width. Googling text-overflow ellipsis not working even suggests this. All the top results (as resent as July 2021) state that a width is required.
Except you don't. I'm not sure when it changed but Ellipsis without specific width](https://codepen.io/unthinkingly/pen/XMwJLG) from 2017 shows us that you don't