OptiGUI

Evidence

Ran on Kiln's test stand (2026-11-04): it stopped at opekope2.optigui.internal.InitializerKt, a class from a jar nested inside the mod; Kiln does not unpack nested jars yet.

What it needs from Kiln

• an access widener
• Mixin
• net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents.EndLevelTick
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Disconnect
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Join
• net.fabricmc.fabric.api.client.screen.v1.ScreenEvents
• net.fabricmc.fabric.api.client.screen.v1.ScreenEvents.AfterExtract
• net.fabricmc.fabric.api.client.screen.v1.ScreenEvents.BeforeExtract
• net.fabricmc.fabric.api.client.screen.v1.ScreenEvents.BeforeInit
• net.fabricmc.fabric.api.event.EventFactory
• net.fabricmc.fabric.api.event.player.UseBlockCallback
• net.fabricmc.fabric.api.event.player.UseEntityCallback
• net.fabricmc.fabric.api.event.player.UseItemCallback
• net.fabricmc.fabric.api.resource.IdentifiableResourceReloadListener
• net.fabricmc.fabric.api.resource.ResourceManagerHelper
• net.fabricmc.loader.api.ModContainer
• net.fabricmc.loader.api.Version
• net.fabricmc.loader.api.metadata.CustomValue
• net.fabricmc.loader.api.metadata.CustomValue.CvObject
• net.fabricmc.loader.api.metadata.ModMetadata
• net.fabricmc.loader.api.metadata.version.VersionComparisonOperator
• net.fabricmc.loader.api.metadata.version.VersionPredicate
• net.minecraft.IdentifierException
• net.minecraft.client.gui.screens.inventory.AbstractContainerScreen
• net.minecraft.client.gui.screens.inventory.BookEditScreen
• net.minecraft.client.gui.screens.inventory.BookViewScreen
• net.minecraft.client.gui.screens.inventory.CreativeModeInventoryScreen
• net.minecraft.client.gui.screens.inventory.HangingSignEditScreen
• net.minecraft.client.gui.screens.inventory.InventoryScreen
• net.minecraft.client.gui.screens.inventory.LecternScreen
• net.minecraft.server.packs.PackType
• net.minecraft.server.packs.resources.PreparableReloadListener
• net.minecraft.server.packs.resources.PreparableReloadListener.PreparationBarrier
• net.minecraft.server.packs.resources.PreparableReloadListener.SharedState
• net.minecraft.server.packs.resources.Resource
• net.minecraft.server.packs.resources.ResourceManager
• net.minecraft.server.packs.resources.ResourceManager.Selector
• net.minecraft.util.Mth
• net.minecraft.util.ProblemReporter
• net.minecraft.world.Container
• net.minecraft.world.Nameable
• and 35 more

On the roadmap: Minecraft's libraries and client API (0.2), Code next to data (0.3), Machines (0.4), Mixin (0.5)

In the author's words

Blazing fast custom GUI textures on Fabric and Quilt with built-in OptiFine custom GUI resource pack support

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file optigui-2.3.0-beta.10+26.3.jar. The scan reads the mod's classes; it does not run them.