Because this specific filename is commonly found on third-party file-sharing sites, the contents are usually a segment of the game's installation data. 🎮 Game Overview: House Builder
When a large game (often several gigabytes) is compressed for sharing, it is split into multiple parts (part1, part2, part3, etc.).
The name House.Builder.Sandbox.Early.Access.part3.rar typically refers to a containing a portion of the game files for the simulation game House Builder .