Thanks for all of your replies. My customer has put this callout in the general notes section of the drawing (the leader line does not point to anything in particular) and is using this to cover any feature on the part they did not give a specific tolerance to.
Received a drawing for a flexible plastic part stating GDT on irregular closed features.
I have no experience with this callout.
Could someone explain it to me. I have attached a picture of the callout.