<highlight-text> is custom CSS that adds a highlighter-pen appearance where it’s applied. It’s defined in the style.css file of my child style, as follows:
highlight-text {background-color:#FFFF00;}
I am using the Text editor. I experimented with Visual once, hated it, went back to Text, and hated Visual even more when I saw what it did to my code.
I’m beginning to think I have no alternative but to look for a replacement editor. After looking for an hour at alternatives, it appears it’ll cost me money to do so. This one looks like the favorite.