I am reading a mathematics textbook (which one is irrelevant, and I do not wish to insult the author if (s)he happens to be reading this). One section relies quite a bit on an appendix and results from several other places, including farther in the book, which leads to a bit of circularity.
In the process of reading it and unwinding it I've decided to rewrite the entire thing, unroll it into a single cohesive section and resolve the singularity, while keeping the content (with a few patches and filled-in holes) essentially the same. It's a total of about 40 pages in the book, but 15-20 unwound.
Obviously me producing this document on my own is just note-taking, and publishing such a thing is silly, but is something in-between acceptable to the community? That is, polishing the document and hosting it on my (public but not well-known) website.
Even with attribution, would this be considered plagiarism? Or even if not, would it be considered rude? I'm a third year graduate student, just barely entering this community, and this seems the best place to ask about social norms within it.
Apologies if this is considered off-topic, but it seems to be related to publishing and plagiarism, which are topics occasionally taken up by this forum.