A common naming style for developers or enthusiasts keeping a "Gold Master" copy of a project to ensure all narrative pieces are preserved in one place.
Often used by community members who have compiled a base game with specific fan-made expansions or translation patches into a single, ready-to-run folder.
This usually adds "After Stories" (content set after the main game's endings), side-stories for secondary characters, or seasonal "fan-disc" content like summer or holiday specials.
You will most likely encounter this specific naming convention in the following areas: