I can't find my old notes, but you've already surpassed them here (well done), and asking OP or GB would sure nail things down.
I think.... the .pup is a pre-mtm1 relic, because it is a zero byte file even in mtm1 tracks. It is absent in mtm2 stock pods (at a glance), but must be present in an mtm1 track for it to function (I discovered this when trying to convert mtm2 to mtm1). I think it was a dead file in mtm1 but was still hooked up, so to speak, but it was unhooked in mtm2 even while a reference for it remained in the .LVL file. Traxx adds it to all pods.
[docpac - mtmtrackedfaq.doc]
Q
: If I wanted to make a night time race, would it be possible? If so, how could I set the light?
A: In the LEVELS Directory, for the track file that you are working on (i.e. MYTRACK.LVL) there will be a line that has something like "earthsky.raw" down in the middle of the file. If you change that entry to "stars.vox" (without the quotes) and save your file off, you should be able to get a night time stars effect for your level. There are some other values down near the bottom that set the light level and the light vector. Their range is from -65535 up to 65536. You can experiment with these to see the effect. Each time that you make a change, you should go into the FOG directory and delete the file associated to your track (MYTRACK.FOG, MYTRACK.LTE). This forces the game to rebuild the fog and light tables for your track. Be very careful doing this and make back ups before editing any of these files.
other:
http://forum.mtm2.com/viewtopic.php?t=1222
<font color=yellow size=+2>Edit:</font>
The .TEX file inside a pod lists all the textures used in a track and the .CLR file holds the data that determines how they are laid out on the terrain (the two files used to convert evo terrain texturing).
.CLR is 131,072 bytes, it's a 256x256 16-bit greyscale raw file (just like evo and cart terrain, which TxRaw will convert to 8-bit if it finds it in a 'data' folder).
.CL0 is 786,432 bytes (131,072 x 6) ?
.CL1 is 262,144 bytes (131,072 x 2) ?
.CL2 is 786,432 bytes (131,072 x 6) ?
zero.raw (78 bytes, from the stock pods) is listed in the mtm level file where .qke is listed in the hellbender level. I replaced zero.raw with a standard terrain texture and nothing happened, I tried viewing it and didn't see much.
fyi, a hellbender data folder, which explains some of the junk in the mtm level file:
DATA\IOWAH.ANI
DATA\IOWAH.GLT
DATA\IOWAH.TDF (still listed in mtm .LVL)
DATA\IOWAH.TXT
DATA\IOWAH2.CL0
DATA\IOWAH2.CL1
DATA\IOWAH2.CL2
DATA\IOWAH2.CLR
DATA\IOWAH2.CRS
DATA\IOWAH2.DEF (still listed in mtm .LVL)
DATA\IOWAH2.LTE
DATA\IOWAH2.NAV (still listed in mtm .LVL)
DATA\IOWAH2.PUP (still listed in mtm .LVL)
DATA\IOWAH2.QKE
DATA\IOWAH2.RA0
DATA\IOWAH2.RA1
DATA\IOWAH2.RA2
DATA\IOWAH2.RA3
DATA\IOWAH2.RA4
DATA\IOWAH2.RA5
DATA\IOWAH2.RAW
DATA\IOWAH2.TEX
DATA\IOWAH2.TTY