The game still runs and the mod works perfectly, but this shows up in the log:
[16:17:41] [Client thread/ERROR] [FML]:
There was a problem reading the entry org/spongepowered/asm/launch/MixinLaunchPlugin.class in the jar C:\Users{COMPUTER_USERNAME}\AppData\Roaming\ModrinthApp\profiles\Weather\mods\3dSkinLayers-forge-mc1.12.2-1.2.0.jar - probably a corrupt zip
net.minecraftforge.fml.common.LoaderException: java.lang.IllegalArgumentException
at net.minecraftforge.fml.common.discovery.asm.ASMModParser.(ASMModParser.java:63) ~[ASMModParser.class:?]
at net.minecraftforge.fml.common.discovery.JarDiscoverer.findClassesASM(JarDiscoverer.java:102) [JarDiscoverer.class:?]
at net.minecraftforge.fml.common.discovery.JarDiscoverer.discover(JarDiscoverer.java:77) [JarDiscoverer.class:?]
at net.minecraftforge.fml.common.discovery.ContainerType.findMods(ContainerType.java:47) [ContainerType.class:?]
at net.minecraftforge.fml.common.discovery.ModCandidate.explore(ModCandidate.java:74) [ModCandidate.class:?]
at net.minecraftforge.fml.common.discovery.ModDiscoverer.identifyMods(ModDiscoverer.java:93) [ModDiscoverer.class:?]
at net.minecraftforge.fml.common.Loader.identifyMods(Loader.java:427) [Loader.class:?]
at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:568) [Loader.class:?]
at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:232) [FMLClientHandler.class:?]
at net.minecraft.client.Minecraft.init(Minecraft.java:467) [bib.class:?]
at net.minecraft.client.Minecraft.run(Minecraft.java:4601) [bib.class:?]
at net.minecraft.client.main.Main.main(SourceFile:123) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_442]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_442]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_442]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_442]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
Caused by: java.lang.IllegalArgumentException
at org.objectweb.asm.ClassReader.(ClassReader.java:185) ~[asm-debug-all-5.2.jar:5.2]
at org.objectweb.asm.ClassReader.(ClassReader.java:168) ~[asm-debug-all-5.2.jar:5.2]
at org.objectweb.asm.ClassReader.(ClassReader.java:439) ~[asm-debug-all-5.2.jar:5.2]

Java Version: 1.8.0
Minecraft Version 1.12.2
3d skin layers Version: 1.2.0

Yea, no clue, if it works just don't touch it. 1.12.2 is entirely unsupported, and I don't think I could make new builds for it currently, even if I wanted to. That file is 3 years old 😅.