Well, T> is the basic and first of Testing a drive. So, T stands for Test (from which level, all the tests could be performed).
And as far as F> is concern, it is probably something related with "F"irmware, which suits best as my knowledge.
But, the F> level is usually referred as Fucking level, and normally we HDD professionals use this level as if the drives has been fucked up
" Hey Man, what's up?"
"Nothing much bro, working on a Fucked Alpine" (that means, the drive is in F>mode. lol)