Does anyone know how to open a .dll, .so or .mdc file by chance? What programs would be good to use?
File Extensions
xD
Try to open the files with a hexeditor. 
.dll and .so are compiled binaries for windoof and unix (the same for .mac for ähm mac?! WTF! )
to edit these files, you must have the source code of etmain, etpub, nq, chaos , bla bla bla.
then you need a compiler. visual studio 2010 express for windoof and make or scons for unix. (on a debian system use “apt-get install build-essential and apt-get install scons”)
A mdc file is a 3D model. is a compressed version of a md3 file. to open a mdc/md3 file you need a LEGAL version of Milkshape 
Hmm you can use the Notepad++ Editor, its a very good editor for coding.
And to download the source of svn´s you can use tortoisesvn.
Have fun ^^
for long time ago (lolz 1-2 years?!) i was a server/clan-admin from a realy little clan
i had a jaymod server with some realy crazy weapons. AK47, M4, Dragunov and lot of weapons of etnam mod.
with the hexeditor i had changed the names of the weapons. ^^
it was a little hard work but the result was realy cool ^^
i has “released” a jaymod 2.1.7 binarie without the “Loading” string on the loading screen.
Hehe it was on my beginn on et ^^
Opening a renamed model in a hex editor in order to change texture paths is a quick hack if you want to reskin something and don’t want to change the original model.