Changing item outline glow

[ExpectedIdentifier]

Hi! I want to change the colour of the glow that outlines pickup items when you hover the cursor over them.

I've already managed to change the colour of the glow that is on the entire object by making a copy of and modifying game_object_flash_frag.glsl. I thought the outline would be similar in that you can just modify the RGB values in game_outline_frag.glsl however there doesn't seem to be any RGB values so I guess I'm doing it wrong or that's the wrong file! Anyone have any ideas? Would be a great help

Thanks