For years after it's introduction, we got asked to make attack the default. So we did.
There might be some info here https://code.wildfiregames.com/D4697 but else digging on the forums might help
You cannot open pmd/psa files with Blender yet.
You need to find the equivalent DAE file on the website, and you should be able to import most in Blender.
https://svn.wildfiregames.com/nightly-build/trunk/binaries/data/mods/public/art/meshes/