Background textures for the ElvUI left and right chat boxes.
Open the addons folder before you get started to see what texture you want and to be sure of its spelling!
To load a chat texture open ElvUI options by typing /ec. When the options open you will see "Chat" on the list at the left. Click on it and then scroll down to Panel Texure (Left) and Panel Texture (Right). Here's an example of what to type in both boxes:
Interface\AddOns\ElvUI_ChatTextures\hunter.tga
Once that's typed in be sure to click the "Okay" button that will appear at the end of the box. Do this for both left and right panel textures.
If your chat boxes have turned a bright green then either you did not install the addon correctly (check your folders) or you have miss-typed something (check your spelling).