diff --git a/man/trouble.texi b/man/trouble.texi
index 514fa9f1a20..42813357426 100644
--- a/man/trouble.texi
+++ b/man/trouble.texi
@@ -848,6 +848,15 @@ easier to spot, running under the debugger will take less time, etc.
 However, simplification is not vital; if you can't do this or don't have
 time to try, please report the bug with your original test case.
 
+@item
+A core dump file.
+
+Debugging the core dump might be useful, but it can only be done on
+your machine, with your Emacs executable.  Therefore, sending the core
+dump file to the Emacs maintainers won't be useful.  Above all, don't
+include the core file in an email bug report!  Such a large message
+can be extremely inconvenient.
+
 @item
 A system-call trace of Emacs execution.