It was way back in early May that the kernel source for Sprint and US Cellular Galaxy S4 variants showed up on Samsung's servers. The Verizon and AT&T devices came in the following weeks, but no peep from the T-Mobile version. Well, until today – Samsung just posted the T-Mobile GS4 kernel source in all its glory.
As usual, the Jelly Bean source is available on Samsung's site for any developer-type or curious onlooker to grab. Now that the Tmo source is up, that pretty much takes care of all the Galaxy S4 devices. Enjoy.