Ultimately, a file like No.Mans.Sky.v4.10.GOG.part1.rar is a symbol of . It represents a studio that refused to walk away from a failed launch, instead choosing to release dozens of free, massive expansions. By the time version 4.10 was archived, the game had transitioned from a cautionary tale into the industry gold standard for how to support a community over the long term. 10 update?
A .rar archive of a GOG installer is a digital time capsule. It allows a user to install the game on any machine without an internet connection or a "phone home" check to a server.
Splitting the game into smaller chunks makes downloading more manageable for those with unstable internet connections. If one part fails, you only re-download that specific 2GB or 5GB segment rather than the entire 15GB+ package.
The "GOG" tag in the filename is significant. Unlike Steam, which requires an active client for most games, GOG (Good Old Games) provides installers.