If you're having trouble extracting the file or getting it to work, you might want to try copying it to your local drive before decompressing if you are working from an external device like a Steam Deck or SD card.
If you are looking at a "long post" regarding this file, it likely covers one of the following technical deep dives: alchemy.7z
Readme.txt : Detailed instructions for specific game engines (e.g., GoldSrc, Unreal Engine). If you're having trouble extracting the file or