When a large file or archive is split into smaller parts, each part is usually denoted with a similar name but with an incremental number. For instance, a file might be split into parts named "file.part1.rar," "file.part2.rar," and so on, up to "file.part10.rar" or more, depending on how many parts it is divided into. The ".part10" in your keyword suggests that the file in question is the tenth part of a multi-part archive.
: To ensure the part hasn't been corrupted during transit. FC2-PPV-4493654.part10.rar
The suffix .part10.rar indicates that the original video file has been split into multiple smaller segments using or a similar archiving utility. When a large file or archive is split
In summary, is a specific technical artifact of the digital adult media trade, representing one tenth (or more) of a high-resolution independent production from the FC2 marketplace. : To ensure the part hasn't been corrupted during transit