Most of the information here is for Warzone 3.1 and above.
body.txt
The body.txt file defines droid body components in Warzone 3.1 and earlier.
On Warzone 3.2 and above, you need to use body.ini instead.
Contents
Assimilate:
File location
The "body.txt" that comes with Warzone can be found here:
base.wz or 
base
stats
body.txt
If you want a "body.txt" in your mod, it should be stored here:
<your mod>.wz or <your mod>
stats
body.txt
Availability
Warzone 3.1 and earlier.
For Warzone 3.2 and above, use body.ini instead.
Your mod can include both the body.txt and body.ini if you want it to work on all versions.