Version Info

• Minecraft, 1.12.2
• Core Lib, 1.1.10, tries upgrading to 1.1.11, didn't fix the issue.

Steps to Reproduce
Just try to boot the game.

Crash report (~/logs/latest.log)
https://pastebin.com/6Zvh5dCt

This is a crash I'm getting while trying to add the Tesseract mod to the Divine Journey 2 modpack. I've boiled it down to being CoreLib, as opposed to ConfigLib or the Tesseract mod itself.

Got it! Thanks for the help.

Caused by Phosphor. Phosphor on Forge has been abandoned for years now and its source code is no longer available, so there's not much I can do about it.
Just don't use Phosphor.