It's still all guesswork since noone looked into:
/CONTENT/OGRE1: Ogre1_Debug.cpk, Ogre1_Media1.cpk, Ogre1_Media2.cpk, Ogre1_Media3_1.cpk, Ogre1_Media3_2.cpk, Ogre1_Media3_3.cpk
/CONTENT/OGRE2: Ogre2_Media1.cpk, Ogre2_Media2.cpk, Ogre2_Media3_2.cpk, Ogre2_Media3.cpk, Ogre2_Media5.cpk