** The variable debug-ignored-errors specifies certain kinds of errors<BR>
that should not enter the debugger.  Its value is a list of error
condition symbols and/or regular expressions.  If the error has any
of the condition symbols listed, or if any of the regular expressions
matches the error message, then that error does not enter the debugger,
regardless of the value of debug-on-error.
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This variable is initialized to match certain common but uninteresting
errors that happen often during editing.
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