Probably a stupid Q

What does -T and +T mean?

It refers to tyrosinase present or absent in the animal..
So a T- is a regular Albino
and a T+ is a caramel Albino aka Xanthic Albino

Tyrosinase negative amelanism results in your typical albinos. They are white and yellow because they have no tyrosinase present, which means no melanin (black/brown pigment protein) is manufactured. Tyrosinase positive amelanism is a bit different in that a mutation causes tyrosinase to no longer manufacture melanin, but because the tyrosinase enzyme is still present in their skin, it gives them the "caramel" colour.

no question is a stupid question my son :P