First and foremost, THANK YOU for creating and maintaining this mod! I know its a lot of blood, sweat and tears! I really love this mod and miss it greatly when its not available. And I hope that I am not wasting your time on this with something that I missed!

Vanilla-Hammers 2.0.6-1.16.2

Recently, I updated to a MineCraft 1.16.2 instance and I think there may be an issue with the use of LibCD. I am getting a NoClassDefFoundError with the latest releases of Fabric and Hammers: Caused by: java.lang.NoClassDefFoundError: io/github/cottonmc/libcd/api/tweaker/Tweaker. When I looked at the latest version of LibContainerData (And what version it looks like Hammers Gradle is referencing), it looks like Tweaker code has been removed. Looking through your code, I don't see any direct references to Tweaker. But I do see your LibCD usage in the configurations which leads me to think its in the realm of either LibContainerData or a bad mix of Fabric versions (early Minecraft Version updates). But when debugging, you start at the top and work your way deeper....

Changes that I have tried to fix the issue:

(All have been done thru MultiMC)
Added the libcd-3.0.2+1.16.2.jar to the loader mods.
Downgraded Fabric API to the gradle version: fabric-api-0.19.0+build.398-1.16.jar to fabric-api-0.18.0+build.397-1.16.jar

Crash Report:

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 8/23/20, 9:23 AM
Description: Initializing game

java.lang.RuntimeException: Could not execute entrypoint stage 'main' due to errors, provided by 'libcd'!
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:53)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32)
at net.minecraft.class_310.(class_310.java:423)
at net.minecraft.client.main.Main.main(Main.java:177)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231)
at org.multimc.EntryPoint.listen(EntryPoint.java:143)
at org.multimc.EntryPoint.main(EntryPoint.java:34)
Caused by: net.fabricmc.loader.api.EntrypointException: Exception while loading entries for entrypoint 'libcd' provided by 'techreborn'
at net.fabricmc.loader.EntrypointStorage.getEntrypoints(EntrypointStorage.java:163)
at net.fabricmc.loader.FabricLoader.getEntrypoints(FabricLoader.java:246)
at io.github.cottonmc.libcd.LibCD.onInitialize(LibCD.java:33)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50)
... 19 more
Caused by: java.lang.NoClassDefFoundError: io/github/cottonmc/libcd/api/tweaker/Tweaker
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:398)
at net.fabricmc.loader.util.DefaultLanguageAdapter.create(DefaultLanguageAdapter.java:45)
at net.fabricmc.loader.EntrypointStorage$NewEntry.create(EntrypointStorage.java:114)
at net.fabricmc.loader.EntrypointStorage$NewEntry.getOrCreate(EntrypointStorage.java:101)
at net.fabricmc.loader.EntrypointStorage.getEntrypoints(EntrypointStorage.java:156)
... 22 more
Caused by: java.lang.ClassNotFoundException: io.github.cottonmc.libcd.api.tweaker.Tweaker
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
at net.fabricmc.loader.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:161)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 28 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Render thread
Stacktrace:
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:53)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32)
at net.minecraft.class_310.(class_310.java:423)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.main.Main.main(Main.java:177)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231)
at org.multimc.EntryPoint.listen(EntryPoint.java:143)
at org.multimc.EntryPoint.main(EntryPoint.java:34)

-- System Details --
Details:
Minecraft Version: 1.16.2
Minecraft Version ID: 1.16.2
Operating System: Linux (amd64) version 5.4.0-7642-generic
Java Version: 11.0.8, Ubuntu
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode, sharing), Ubuntu
Memory: 256663552 bytes (244 MB) / 850395136 bytes (811 MB) up to 1073741824 bytes (1024 MB)
CPUs: 12
JVM Flags: 2 total; -Xms512m -Xmx1024m
Fabric Mods:
angerable-patch: Angerable Patch 1.0.0-1.16.1
autoconfig1u: Auto Config v1 Updated 3.2.0-unstable
blue_endless_jankson: jankson +
chainmail: Chainmail 0.3.0
cloth-basic-math: Cloth Basic Math 0.5.1
cloth-client-events-v0: Cloth Client Events v0 1.0.8
cloth-config2: Cloth Config v4 4.7.0-unstable
creativebuttonmover: Creative Button Mover 0.2.5
diggusmaximus: Diggus Maximus 1.3.1-1.16
expandedstorage: ExpandedStorage 5.3.16
fabric: Fabric API 0.19.0+build.398-1.16
fabric-api-base: Fabric API Base 0.1.3+12a8474cfa
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.4+c6a8ea894e
fabric-command-api-v1: Fabric Command API (v1) 1.0.8+5ce533984e
fabric-commands-v0: Fabric Commands (v0) 0.2.0+52d308364e
fabric-containers-v0: Fabric Containers (v0) 0.1.8+045df74f4e
fabric-content-registries-v0: Fabric Content Registries (v0) 0.1.9+059ea8664e
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.2+b7f9825d4e
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.0+e2e6cdad4e
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.0+16acbe5b4e
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.1+91555cd14e
fabric-item-api-v1: Fabric Item API (v1) 1.1.0+29679fd64e
fabric-item-groups-v0: Fabric Item Groups (v0) 0.2.0+438f96364e
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.1+730711c64e
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.0+3fa9f7c54e
fabric-language-kotlin: Fabric Language Kotlin 1.3.72+build.1
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.2.0+74cc3b204e
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.0.0+fac8f3664e
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.2+b764ce994e
fabric-models-v0: Fabric Models (v0) 0.1.0+dfdb52d64e
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.5+b50ffc7b4e
fabric-networking-v0: Fabric Networking (v0) 0.1.10+e00ecb5f4e
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.6.0+e81ec80b4e
fabric-object-builders-v0: Fabric Object Builders (v0) 0.6.1+ba4afa574e
fabric-particles-v1: fabric-particles-v1 0.2.1+0a6f2a704e
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.4.3+e5d3217f4e
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.2.13+eae12eb84e
fabric-renderer-indigo: Fabric Renderer - Indigo 0.3.4+5d32f5834e
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.1.0+e2862de64e
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.3+b7f9825d4e
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.10+e5d3217f4e
fabric-rendering-v0: Fabric Rendering (v0) 1.1.0+534104904e
fabric-rendering-v1: Fabric Rendering (v1) 1.2.0+fc24ff244e
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.2.9+e5d3217f4e
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.1.0+872498414e
fabric-structure-api-v1: Fabric Structure API (v1) 1.0.0+516ece7c4e
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 1.0.3+ac8e8c594e
fabric-textures-v0: Fabric Textures (v0) 1.0.4+eae12eb84e
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.2.2+ccce563e4e
fabricloader: Fabric Loader 0.9.2+build.206
glassdoor: Glass Doors 1.4.4-1.16
gravestones: Gravestones 1.4.0
harvest: Harvest 1.2.12
improved-stations: Improved Stations 2.0.3
inventorysorter: Inventory Sorter 1.7.2-1.16
jankson: Jankson 3.0.1+j1.2.0
kyrptconfig: Kytpt Config 1.1.2-1.16
libblockattributes: LibBlockAttributes 0.7.0
libblockattributes_core: LibBlockAttributes (Core) 0.7.0
libblockattributes_fluids: LibBlockAttributes (Fluids) 0.7.0
libblockattributes_items: LibBlockAttributes (Items) 0.7.0
libcd: LibCapableData 3.0.2+1.16.2
libmultipart: LibMultiPart 0.4.0
libnetworkstack: Lib Network Stack 0.4.0
libstructure: LibStructure 1.5
magna: Magna 1.4.0-1.16.2
minecraft: Minecraft 1.16.2
modmenu: Mod Menu 1.14.6+build.31
ninjaphenix-container-lib: NinjaPhenix's Container Library 1.1.5
org_jetbrains_annotations: annotations 17.0.0
org_jetbrains_kotlin_kotlin-reflect: kotlin-reflect 1.3.72
org_jetbrains_kotlin_kotlin-stdlib: kotlin-stdlib 1.3.72
org_jetbrains_kotlin_kotlin-stdlib-jdk7: kotlin-stdlib-jdk7 1.3.72
org_jetbrains_kotlin_kotlin-stdlib-jdk8: kotlin-stdlib-jdk8 1.3.72
org_jetbrains_kotlinx_kotlinx-coroutines-core: kotlinx-coroutines-core 1.3.7
org_jetbrains_kotlinx_kotlinx-coroutines-jdk8: kotlinx-coroutines-jdk8 1.3.7
reborncore: Reborn Core 4.4.0+build.67
repurposed_structures: Repurposed Structures 1.5.1
roughlyenoughitems: Roughly Enough Items 5.2.7
roughlyenoughitems-api: REI (API) 5.2.7
roughlyenoughitems-default-plugin: REI (Default Plugin) 5.2.7
roughlyenoughitems-runtime: REI (Runtime) 5.2.7
simple_pipes: SimplePipeTest 0.4.0
simple_pipes_dep_container: SimplePipeTest (Dependency Container) 0.4.0
staticdata: Static Data 1.1.2
team_reborn_energy: Energy 0.1.0
techreborn: Tech Reborn 3.5.1+build.101
trees-do-not-float: Trees Do Not Float 1.12.94
vanilla-hammers: Vanilla Hammers 2.0.6-1.16.2
voxelmap: VoxelMap 1.10.10
waila: Hwyla 1.9.22
Launched Version: MultiMC5
Backend library: LWJGL version 3.2.2 build 10
Backend API: NO CONTEXT
GL Caps:
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fabric'
Type: Client (map_client.txt)
CPU:

IIRC, LibCD removed Tweakers in the 1.16.2 update (3.0.0+). VH doesn't touch them. Is there a chance another mod you have is using Tweakers while assuming the LibCD version is <= 1.16.1 (like, a mod that hasn't been fully updated to 1.16.2, but still "works")?
edit: seems to be TechReborn:
Caused by: net.fabricmc.loader.api.EntrypointException: Exception while loading entries for entrypoint 'libcd' provided by 'techreborn'

I am really sorry Draylar! I have updated a thread that was left on Tech Reborn with the information... Again, Thank you!

Happy to help!