Because ".rar" is a WinRAR compression format, "1-6" often simply denotes a range of items.

Below are the most likely interpretations and write-up themes for this topic:

It may represent "Volumes 1 through 6" of a larger dataset that was split to bypass email or server upload limits.

These files usually contain textures, scripts, or patches. For example, a "No glowing eyes" mod or a specific weapon overhaul might be packaged this way for easy extraction into a game’s "Data" folder.

It is sometimes used for batch-downloaded research papers or dissertations from platforms like UCL Discovery or ProQuest.

2-20474-1-2-1539703265.7z 1250.53 - Extracting Immersive Dawnguard Dayspring Pass (IDDP)-4126-1-0-3.7z 1250.79 - Extracting IDDP - Official Long Tan After Action Reports

The archive typically includes Official After Action Reports (AARs), intelligence summaries, and patrol logs from the 1960s.