Strange Icon - Working with Pivot tables

[HW]

I have noticed a strange picture/icon (Can't paste it here) A small icon
with a Blue J and a yellow background. I can identify it or it's purpose.

Anyone know what it is? What it does?

Thank and Seasons Greeting!

 

[Debra Dalgleish]

What version of Excel are you using?
Where/when does the icon appear?