ZT is the policy-sensitive end of the Treasury complex, tracking expectations for the next couple of years of Federal Reserve decisions more closely than anything else that is physically deliverable. It is the standard second leg of a curve steepener or flattener against zn or zb.
Note the doubled face value: $200,000, not $100,000, chosen so that the contract's dollar risk is not trivially small. Traders who assume $100,000 will size curve trades wrongly by half.
Example: ZT at 102'2875 is 102 + 28.75/32 = 102.898, so $205,797. DV01 near $38. A steepener of 10 ZN against ZT needs roughly 10 x 65 / 38 = 17 ZT contracts to balance the risk.
Related: treasury-futures, zn, zf, dv01, yield-curve