: This indicates the resolution. We are looking at ultra-high-definition video content, which explains why the file is split into many parts.
: Always run the file through a tool like VirusTotal before extraction. C0ntr4t1sta.4K.yamil.part12.rar
: Often a "tag" for the uploader or the group that encoded the file. : This indicates the resolution
You must have (Part 1 through Part X) in the same folder. C0ntr4t1sta.4K.yamil.part12.rar