I should have described the differences, but I would have wanted to perform some interpretation and did not feel comfortable doing so.
For example, one item [1] there that interests me is a set of student-taken notes that has been on the lecturer's website [2] for seven years. My prediction is that it will never be changed or fed to a publisher. I think that in trying to avoid conflict with publishers and blame for unstable and error-filled texts the sentence you quote saps the enthusiasm of the visitor.
[1] https://www.ams.org/open-math-notes/omn-view-listing?listing...