: This indicates the file is part of a complete collection containing all previously released faces up to a certain version.

: You cannot open or use .part04.rar alone. You must download all parts (e.g., parts 1 through 15) and use a tool like WinRAR or 7-Zip to extract them. Right-clicking "Part 01" and selecting "Extract" will automatically pull data from all other parts to recreate the full folder. Popular Facepack Sources

If you are looking for the other parts or instructions, they are typically found on community hubs: