Hello here is the Launcherlog of my minecraft:
18:47:53.294
launcher
main
Have local file /home/tha/.minecraft/libraries/org/scala-lang/scala-xml_2.11/1.0.2/scala-xml_2.11-1.0.2.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.310
launcher
main
Couldn't fetch SHA1 checksum for http://files.minecraftforge.net/maven/org/scala-lang/scala-swing_2.11/1.0.1/scala-swing_2.11-1.0.1.jar
18:47:53.310
launcher
main
Have local file /home/tha/.minecraft/libraries/org/scala-lang/scala-swing_2.11/1.0.1/scala-swing_2.11-1.0.1.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.317
launcher
main
Couldn't fetch SHA1 checksum for https://libraries.minecraft.net/lzma/lzma/0.0.1/lzma-0.0.1.jar
18:47:53.317
launcher
main
Have local file /home/tha/.minecraft/libraries/lzma/lzma/0.0.1/lzma-0.0.1.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.318
launcher
main
Couldn't fetch SHA1 checksum for https://libraries.minecraft.net/java3d/vecmath/1.5.2/vecmath-1.5.2.jar
18:47:53.318
launcher
main
Have local file /home/tha/.minecraft/libraries/java3d/vecmath/1.5.2/vecmath-1.5.2.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.318
launcher
main
Couldn't fetch SHA1 checksum for https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.6/jopt-simple-4.6.jar
18:47:53.318
launcher
main
Have local file /home/tha/.minecraft/libraries/net/sf/jopt-simple/jopt-simple/4.6/jopt-simple-4.6.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.318
launcher
main
Couldn't fetch SHA1 checksum for https://libraries.minecraft.net/net/sf/trove4j/trove4j/3.0.3/trove4j-3.0.3.jar
18:47:53.318
launcher
main
Have local file /home/tha/.minecraft/libraries/net/sf/trove4j/trove4j/3.0.3/trove4j-3.0.3.jar but don't know what size or hash it should be. Have to assume it's good.
18:47:53.708
launcher
main
Checking installations.
18:47:53.708
launcher
main
Minecraft client 1.8.9-forge1.8.9-11.15.1.1855 is ready to start.
18:47:53.708
launcher
main
Starting!
18:47:53.724
launcher
main
Using default game log configuration client-1.7.xml (outputs XML)
18:47:54.622
LaunchWrapper
main
Loading tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker
18:47:54.777
LaunchWrapper
main
Using primary tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker
18:47:54.777
LaunchWrapper
main
Calling tweak class net.minecraftforge.fml.common.launcher.FMLTweaker
18:47:54.847
FML
main
Forge Mod Loader version 11.15.1.1855 for Minecraft 1.8.9 loading
18:47:54.848
FML
main
Java is OpenJDK 64-Bit Server VM, version 1.8.0_252, running on Linux:amd64:5.3.0-62-generic, installed at /usr/lib/jvm/java-8-openjdk-amd64/jre
18:47:55.020
FML
main
The coremod net.labymod.core.asm.LabyModCoreMod does not have a MCVersion annotation, it may cause issues with this version of Minecraft
18:47:55.022
FML
main
Loading tweaker optifine.OptiFineForgeTweaker from OptiFine 1.8.9 HD U L5.jar
18:47:55.026
FML
main
Loading tweaker optifine.OptiFineForgeTweaker from preview_OptiFine_1.16.1_HD_U_G2_pre2.jar
18:47:55.045
FML
main
Loading tweaker org.spongepowered.asm.launch.MixinTweaker from salhack-github-2.05-release.jar

I think its from the 2b2t client salhack but the launcher version is actually 2.1.15166 but i cant choose it at the start of the page.

Im Sorry for my bad English