When you’re viewing changes to a markdown file, you have the option to compare the rendered versions in the diff view.
Let’s say you wanted to view the diff of my latest commit to my README.md in my random-example repo. By default you are looking at the raw markdown contents, i.e. the “source diff.”
But suppose you wanted to view the actual rendered markdown file as a diff. Click on the Display the Rich Diff button located in the upper right.
Now you’ll see the diff of the README.md file as a rendered file.