Wait what? I'm not sure of the context here, but I believe the EDuke32 source code is located here.

Oh man I actually have a physical copy of the level design handbook! There's 333 pages though... Do you need the CD ISO as well?

It's a thread with a massive collection of weapon / enemy / misc. sprites for use in creating TCs. Some really good content in there. I can send you a zip if you want?