Master Variable List for entire workflow

[MikeD]

It would be very helpful if there was a master variable list for the entire workflow, with one column of that list being the first tool number where the variable appeared.  For example, when using JOIN with many fields, it is pretty easy to get duplicate fields.  It is also common to have fields that are only slightly different, for example, "Variable_1" and "Variable 1."  If there was a master list of variables with hotlinks to the first tool where a variable appeared, it would be easy to fix duplicate or near-duplicate variables.  Other useful fields for a variable summary would include the variable type (integer, double, etc.), whether the field has any nulls, and whether the field has any text.