[pablo_c]

Hi! I created the post. Will answer your points below:

- There was no editor, or more precisely, I was the editor. What you are addressing is interesting. The two proofreaders, both grammatical and the technical work directly on the ".Rmd" (r markdown). I had to explain -in the grammatical case- "what to change" and what "not to change" about the markdown syntaxes. Even more, if you are working with R package bookdown, you can correct some figure captions, text links, and so on... all of this is r markdown syntax; the proofreader had to change with caution all of this.

- You are right about you don't need an ISBN to publish on gumroad. Just for Amazon (or other publishers).