Hi there!
I found out a "IneQuation: wavetrant (WTF is this?)" in some of the code (tr_shader.c, en of ParseTexMod method).
Wavetrant & Wavetrans are use for translating the texture along the t or s coord (wave-tran-t & wave-tran-s) using a specified function:
"tcmod wavetrant sin .5 1 0 2" would translate the texture along the t-axis using a sin function of base value '.5', amplitude '1', frequency 2, with no dephasing.
Here's another example:
"tcmod wavetrans square 0 0.5 0 1"
This would translate the texture along the s-axis (wavetrans), with a square function of base 0, amplitude 0.5 & frequency 1. So the texture would be right-placed, and then get left-placed 0.5 second later (half-period), and get back to the right 0.5 second later, and so on.
You can check that in the original MOHAA game.
Enjoy!