: Specifies that this is the first part of a "split" archive. The Nature of Split Archives
: Likely a project name or shorthand for "Russia" or a specific software version. RUS-8.7z.001
Without knowing the source of the file, it is impossible to determine if the content is a map expansion for a simulator, a historical dataset, or a system backup. Writing an essay on the file itself would be like writing a biography of a locked box without knowing what is inside. : Specifies that this is the first part of a "split" archive
: Indicates the file was compressed using the 7-Zip archiving tool. a historical dataset