A tool is needed for auditing Conditional Formatting formulae
Conditional formatting allows a formula as part of a rule, and that formula may refer to another cell in the workbook. If that other cell is deleted, then a #REF error creeps into the conditional formatting formula.
Of course a properly constructed formula would allow for such circumstances, but there is no simple method to check the conditional formatting rules to validate them.
It would be helpful to have a way to download the conditional formatting rules to allow the programmer to audit those rules.