Describe the bug
Whem Supplementaries and Alexis Caves installed game crash on world load/creation.

To Reproduce
Steps to reproduce the behavior:
install mods:

boot minecraft
create new world

Expected behavior
World load

Actual behavior
MInecraft crash

Logs
latest.log
crash-2023-12-01_15.17.08-server.txt

This looks like an issue with Supplementaries not liking something related to banners. This mod doesn't have anything to do with banners, so you will need to investigate elsewhere.

Issue is from this mod.read the log explains it all, forge logs the error too. You are loading sheet class too early

Thanks for the report; I see the problem now. 2.6.1 (out shortly) should fix it.