Pandoc Markdown Lecture Template: This project defines a skeleton repo for creating lecture slides and handouts including lecture notes out of Pandoc Markdown (https://pandoc.org/MANUAL.html) using a single source approach.
So, the take away for me is that I have to use the % format instead of the < format because the way Hugo handles things internally. Additionally, I want to use relref instead of ref, because I want to generate an internal link with the ref.
see https://github.com/McShelby/hugo-theme-relearn/issues/681#issuecomment-1754767292: