From looking into this a bit, it basically says "for all shaders, check the (index buffer and vertex buffer) texture overrides and apply them".
In this case, instead of looking for pixel or vertex shaders you look for index buffers and/or vertex buffers and skip those with texture overrides.
Unfortunately the texture overrides don't seem to do much (if anything) by themselves in these games (although you can disable them easily while hunting), so you need to list specific shaders and then tell them to look for texture overrides to apply.
But since there's a lot of shaders, finding the ones that use these textures can be a big hassle (especially if hashes change between game versions), and so it's easier to just make all shaders look for texture overrides with a wildcard (using ShaderRegex without specifying any conditions).
For the game I was looking at, the buffer also seemed to contain the pussy textures, so removing it removed all definition from that area. Removing it from only some shaders removed the mosaic but made it flicker in and out of existence, and the texture had some very hard edges... which might just be because it wasn't designed to be used without the mosaic.
