日本語の説明があります。Lightweight JSON-driven in-game guides for NeoForge 26.x. Content mods add data/<modid>/guide/ — players read from the Codex. Book & tablet themes, optional JEI.
Codex screen — multiple books listed
Guide book index (2-column, icons)
Entry page — crafting recipe
Codex Tablet theme
Example book entry (welcome)