I built this approach at a hackathon with a friend, it's something that enables people to teach about code by inspecting different parts of a pre-existing project: https://www.codetours.xyz/
Never took the extra time to polish it up after the hackathon, but if someone is interested I'd be happy to work together on improvements.
I already posted to the original but thought I would chime in. I like the idea of guiding someone through some code with a narrative. Your tool is very helpful for this.
I have a similar tool but it allows the comments to be added to the code as it evolves:
The main difference being that the context of the comment is always in line with code at the point the comment is made. One other difference is that a person can add drawings and audio to their comments.
Never took the extra time to polish it up after the hackathon, but if someone is interested I'd be happy to work together on improvements.