What does TST mean?

TST stands for ton sur ton, which is French for 'tone on tone'. the monogram is the same color as the fabric of the bag, like this:

josephinepm001.jpg
 
Thanks monkeydog. I thought the logo will always match with the background. If it's not TST, what color is the logo?

The normal "non-TST" mini's have a lighter canvas background and a dark prominent logo (e.g., the cherry or the blue). The TST's have a darker background than the logo.

e.g.,
p10903641_ph_althero_Cerise.jpg
vs.
p10903641_ph_althero_Khaki_TST.jpg