Component Viewer

Evidence

Ran on Kiln's test stand (2026-11-04): FabricComponentViewer did not start: java.lang.NoClassDefFoundError: net/minecraft/client/gui/screens/options/OptionsSubScreen.

What it needs from Kiln

• an access widener
• Mixin
• com.mojang.authlib.GameProfile
• com.mojang.blaze3d.platform.InputConstants.Key
• net.fabricmc.fabric.api.event.EventFactory
• net.minecraft.client.KeyboardHandler
• net.minecraft.client.OptionInstance
• net.minecraft.client.OptionInstance.CaptionBasedToString
• net.minecraft.client.OptionInstance.Enum
• net.minecraft.client.OptionInstance.IntRange
• net.minecraft.client.OptionInstance.TooltipSupplier
• net.minecraft.client.OptionInstance.ValueSet
• net.minecraft.client.OptionInstance.ValueUpdateListener
• net.minecraft.client.Options
• net.minecraft.client.ScrollWheelHandler
• net.minecraft.client.gui.components.AbstractWidget
• net.minecraft.client.gui.components.Button
• net.minecraft.client.gui.components.Button.Builder
• net.minecraft.client.gui.components.Button.OnPress
• net.minecraft.client.gui.components.OptionsList
• net.minecraft.client.gui.components.Tooltip
• net.minecraft.client.gui.components.toasts.Toast
• net.minecraft.client.gui.components.toasts.Toast.Visibility
• net.minecraft.client.gui.components.toasts.ToastManager
• net.minecraft.client.gui.screens.options.OptionsSubScreen
• net.minecraft.client.gui.screens.options.controls.KeyBindsScreen
• net.minecraft.client.input.KeyEvent
• net.minecraft.client.input.MouseButtonInfo
• net.minecraft.client.renderer.RenderPipelines
• net.minecraft.client.server.IntegratedServer
• net.minecraft.core.RegistryAccess
• net.minecraft.core.component.DataComponentMap
• net.minecraft.core.component.DataComponentPatch
• net.minecraft.core.component.DataComponentType
• net.minecraft.core.component.Removed
• net.minecraft.core.component.TypedDataComponent
• net.minecraft.nbt.NbtOps
• net.minecraft.nbt.Tag
• net.minecraft.nbt.TextComponentTagVisitor
• net.minecraft.network.chat.FormattedText
• net.minecraft.network.chat.FormattedText.StyledContentConsumer
• net.minecraft.network.chat.Style
• and 27 more

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

In the author's words

Component Viewer is a mod for Minecraft Java Edition that allows you to view and copy components of any item stack.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file componentviewer-fabric-1.3.6+26.3.jar. The scan reads the mod's classes; it does not run them.