Maybe I miss something, but it is not trivial thing to do. I just tried to switch debug buffer to fundamental mode and run debugger-step-through. It lead to the buffer changing back to debug-mode. Not running debugger commands in debugger buffer would be useless. I imagine that similar issues may exist for other types of non-file buffers. Eli Zaretskii writes: >> From: Ihor Radchenko >> Cc: emacs-devel@gnu.org >> Date: Fri, 26 Oct 2018 15:00:09 +0800 >> >> I would like to point out that the long line problem also exists for >> non-file buffers. >> Specifically, evaluating debug-on-entry for org-mode buffer parsing >> functions often leads to ridiculously long lines (pretty much the whole >> buffer is transformed into a single line), which takes forever to >> display. >> find-file-literally does not help with this problem at all. > > The equivalent of find-file-literally for non-file buffers is use a > unibyte buffer in Fundamental mode.