When saving a buffer using `C-x s` (save-some-buffers), I sometimes want to do a `d` for diff-buffer-with-file. How does one scroll down on the new buffer with the diff results to see all the changes?

Sounds like you want `scroll-other-window(-down)` bound to `C-M-v` and `C-M-S-v` respectively. See `other-window-for-scrolling` if your window setup requires it. Edit: > if your window setup requires it I just tried to check whether window placement for the diff mattered but noticed instead that scrolling a buffer too small (no content to scroll to, up or down), it errors out and quits you out of the diff, if that annoys you, you could advice around the scrolling functions and `ignore-error(s)`. But looking more closely, there's `save-some-buffers-action-alist` where you could also add 2 keys to scroll ignoring boundary errors

Thank you!