napkin VS ra

GitHub is definitely a viable choice for this sort of project, as this example I recently discovered illustrates. Another possible option, especially for LaTeX-based documents, might be something like Overleaf, though you'd have to think carefully about what permissions you'd want to grant to strangers in terms of modifying your original work. But ultimately, I'd defer to others about the best ways to make your work available in a way that encourages comments and interactivity.

I have some notes that I have been taking for my course via LaTeX. I aim to share my notes. Originally I was planning to share them at the end, but then I came across this repo: https://github.com/vEnhance/napkin/

I remember posting a similar list for introductory analysis (like the kind commonly required for math majors) too, but I didn't bother to figure out where that was, so I just looked up Volume I of the book by Jiří Lebl and found another good explanation of it, including cases where the function to be integrated is not continuous.

I also found one where the only comment that would be useful to anyone other than the OP was mine; I recommended, as far as free resources go, the textbooks by Lebl and by Trench.

Lebl's "Basic Analysis: Introduction to Real Analysis" is opensource and the sourcecode's on github here