Files that are split into parts, such as "FC2-PPV-3175924-2-4K.part05.rar", are typically the result of dividing a large file into smaller, more manageable pieces. This can be done for several reasons:
When reviewing or evaluating RAR files, especially those that are part of a larger set (indicated by ".part05" in your example), consider the following steps: FC2-PPV-3175924-2-4K.part05.rar