Downloading files from sites listing such RAR segments carries significant risks:
Safety and Security Risks with Third-Party Archive Downloads FC2-PPV-4450104.part05.rar
: All sequential parts must reside in the exact same folder on your computer storage drive. Downloading files from sites listing such RAR segments
Download and install a modern extraction tool capable of reading multipart archives. FC2-PPV-4450104.part05.rar
In essence, the complete file name tells you that you are looking at the fifth piece of a large, compressed archive originating from the FC2 platform.