These are alternate graphics for global objects such as pipes, ? Blocks, Turn Blocks, and Bullet Bill Blasters. The .zip also contains an ExGFX file that has skinny pipes, connected pipes, a diagonal pipe, and 3-tile-wide giant pipes a la SMB3 World 4. Most of these tiles do not require custom palettes, but the ON frame for the ON/OFF Block and the Red ! Block do, so a custom palette for those is included.