Crash at start with Sandwichable mod.
Version: appleskin-fabric-mc1.16.x-2.1.0 + sandwichable-1.2-beta5--1.16.5
Logs: https://pastebin.com/9qUY1Rg6

Looks similar to the incompatibility in #115. Sandwichable will probably want to use the AppleSkin API instead of applying a mixin to AppleSkin classes:

https://github.com/squeek502/AppleSkin/tree/1.16-fabric#for-mod-developers

Yes, sandwichable was originally adding compatibility before the new API was added, and the old "API" consisted of an interface to implement over item classes, preventing me from reasonably making appleskin an optional dependency.