find-file-read-only-other-window
find-file-read-only-other-window is an interactive compiled Lisp function in `files.el
'.
It is bound to C-x 4 r.
(find-file-read-only-other-window FILENAME &optional WILDCARDS
)
Edit file FILENAME in another window but don't allow changes.
Like C-x 4 C-f, but marks buffer as read-only.
Use C-x C-q to permit editing.