Those are mipmap levels. Textures that have an "m" in the filename are a mipmap texture, such as the texture you are seeing: tex1_64x32_m_d942b886ec8b4d4f_4. Mipmaps are used to give an environment the feeling of depth as the texture is tiled farther into the distance. This is not the best example especially since it's Xenoblade, but its the one I have ready: No Mipmaps - With Mipmaps
They can also be internal to the texture itself. Dolphin does not use these levels, but Dolphin Ishiiruka does. My tool by default generates them with the Dolphin format (mip1, mip2, etc) to ensure compatibility with both Dolphins, but can be switched to internal if the pack is only for Ishiiruka.
They can also be internal to the texture itself. Dolphin does not use these levels, but Dolphin Ishiiruka does. My tool by default generates them with the Dolphin format (mip1, mip2, etc) to ensure compatibility with both Dolphins, but can be switched to internal if the pack is only for Ishiiruka.