What is code U, V, W, X, Y or Z. On Box 14 of my W-2 its TRS Retirement what category is it?

TRS is listed in Box 14 for informational purposes only. Report the amount in box 14 and select Other.  These contributions are post-tax and don't impact your tax return.

For letters in box 12 please check: What do the letter codes in box 12 of my W-2 mean?