I am currently building a blog using the Jekyll static site generator and Github Pages. I would like to eventually work directly on the CSS and HTML and get rid of Jekyll altogether.
In one of the
div elements in my site I see that the class
language-plaintext is assigned. However this class does not occur in the CSS. Where does this class come from ?
language-plaintext class is applied to Markdown code blocks  by Jekyll build process. An example of Markdown code block
``` Hello World! ```