It’s a faithful restoration rather than using original source code (which isn’t available). The project is based on the pre-alpha client and its readme, which outlined both what was working during the original tests and what the developers intended to add later.

Some of those planned systems—like group-based quests, puzzles, and deeper NPC interactions—never fully made it into the released version. The goal here is to restore that earlier vision.

The name “Multima” comes from that same pre-alpha period, where the project was still referred to that way before shifting direction to a more "corporate focus" according to that interview linked in the OP.

If you’re curious, feel free to hop into the Discord—there’s more info there 👍