Connected Textures Mod (1.18.12, 1.18.2) (CTM), adds extensions to the vanilla model system that allow for more complex contextual rendering. This mod allows resource pack to add connected textures and emissive rendering.
This mod attempts to render everything exactly as it is written. There is no ASM hook to render 1.7-style, all rendering is done via baked models. CTM transforms the vanilla baked model and adapts it to the additional rendering effects defined in the CTM JSON data. It also allows mods and resourcepacks the ability to completely ignore CTM. They can render something completely different when CTM is present, provided they have a few more lines of JSON.