Stephen J Turnbull <turnbull(a)sk.tsukuba.ac.jp> writes in xemacs-beta(a)xemacs.org:
... Is there a way to turn them into an error (so that you can setq
debug-on-error t before "doing that")? I've found them hard to
localize because XEmacs doesn't stop when they occur.
Other than putting a breakpoint in `eq_with_ebola_notice' under a
debugger, no.