From Mods Repository Wiki
Animations in CoDWaW typically have a prefix such as ch_ for character, o_ for object, v_ for vehicle, p_ for player, etc... Otherwise animations will typically have a straight forward prefix for what they are such as stuka_ or patrol_.
animTrees (.atr) files contain all the animations used in the game. The animTrees are a series of lists that tell an entity what animations to use, while the animScripts take care of how a lot of the regular animations are handled on entities such as walk, running, firing, and idle animations.
The animTrees (.atr files) can be opened in just about any text editor like WordPad, NotePad, Ultra Edit, etc...
A big chunk (if not all) of AI body animations are inside generic_human.atr. If you see a specific animation in a level when playing the game, you can do a search for the level name and you will come across the list of animations for that level. For example, searching for "Oki3" takes us to a list called "level_oki3", the first few animations being:
ch_oki3_tunnel_discover //regroup at the gate Ch_oki3_regroup_sarge_talk Ch_oki3_regroup_sarge_order Ch_oki3_regroup_marine_talk
We can use any of the animations with the ch_ prefix on an AI by simply defining it in our script, for example:
level.scr_anim["sarge"]["meet_by_wall"] = %Ch_oki3_regroup_sarge_order;
Another good location to find an animation that you may recall from a level is in the level's _anim script file.
oki3_anim.gsc has a long list of scr._anims and scr._sounds, a small snippet from the gsc:
// "Open fire!" level.scr_sound["sarge"]["open_fire"] = "Oki3_IGD_244A_ROEB"; // "Clear the area!" level.scr_sound["sarge"]["clear_area2"] = "Oki3_IGD_245A_ROEB"; // "Miller - man that MG!" level.scr_sound["sarge"]["man_mg"] = "Oki3_IGD_246A_ROEB";
The folder with all the game animation files is another good place to see what animations are available.
Sources: Treyarch's Wiki