https://github.com/Kobata/inventory-tweaks/blob/develop/src/main/java/invtweaks/InvTweaksObfuscation.java#L95 ignores container behavior, potentially leading to retrieval of wrong slot, because other mods may use Access Transformation to override its behavior. I suggest using AT to retrieve proper method.

Because original method is private, using AT is safe and will not lead to reduction of visibility in subclasses.