The VaLNGOS (Valheim Large Network Game Object Server Suite) is a "from scratch" open-source implementation of the Valheim game server. The project's priorities include: enabling high performance 1000+ slot servers, ease of mod scripting and third party integration, un-modded client compatibility, and community driven leadership.
UPDATE #1: The VaLNGOS Core's feasibility has been proven. Connecting to servers and switching basic movement packets has been achieved. We are now working on FFI bindings for Steamworks and will proceed to implement a MVP.
The project is currently in the research phase. We are reverse engineering the game's networking code and planning a strategy for the server pipeline. Videos demonstrating basic behavior will come soon.