Dummy helper
 

The locator, is that a dummy helper, something I can use to link items to it, but itself does not do anything ?..

I am looking for a dummy helper

Yes, a locator is used often for that purpose. Sometimes I draw a symbol with curves or use text as dummies. It's easier to associate them to what they do if there are many of them...

tnx

excellent script Danny !.. tnx

You can also make any object you want into a non-rendering dummy by turning off all of it's render stats.