I came across the image below on social network and I feel quite excited about the line. I wonder if anyone knows what is the book (maybe a paper or an introductory note)? To the best of my knowledge, I do not think it comes from a book on étale cohomology; at least not among the well-known ones like Milne, Leifu, Freitag, Tamme, etc.
This is from the preface of "Lectures grothendieckiennes" by Frédéric Jaëck et al. The preface (and in particular this footnote) is written by Peter Scholze. You can read the book online for free (at time of writing) at https://spartacus-idh.com/094.html