Variable: debug-on-quit
debug-on-quit is a customizable variable defined in eval.c.
Value
nil
Documentation
Non-nil means enter debugger if quit is signaled (C-g, for example).
Does not apply if quit is handled by a condition-case.
Probably introduced at or before Emacs version 17.
Source Code
// Defined in /usr/src/emacs/src/eval.c
DEFVAR_BOOL ("debug-on-quit", debug_on_quit,
doc: /* Non-nil means enter debugger if quit is signaled (C-g, for example).
Does not apply if quit is handled by a `condition-case'. */);