This line causes ShowMeWhatYouGot and indirectly Identifier to be loaded during Mixin preparation when an old version of calio is installed. This means that any Mixins into Identifier silently fail, causing malte0811/FerriteCore#59. You should never directly reference classes that can be transformed by Mixin in a mixin config plugin.

Thanks for the tip, I'll keep it in mind in the future.
For the new version I just uploaded (1.0.1), I removed the mixin plugin completely as the new version of Calio (1.5.0, for Minecraft 1.18.2) removes the necessity for this compatibility mixin.