I think something perhaps @Joachim_Ante_1 missed in my original post was that I only saw warnings, but the warnings were being processed as errors, and there’s seemingly no way to disable the package using warning-as-errors. Personally, I 100% don’t care about warnings in packages - it’s internal code, and shouldn’t affect me in any way. If we could have the package as a DLL instead, that would be perfect. And having its dependencies as versioned DLLs too, so that we can have multiple versions coexisting, would be the icing on the cake.
Anyway, between this and the GetSingleton exception spam ( NullReferenceException when calling EntityQuery.GetSingleton<T>() in a SystemBase in 0.9.0 ), I have no choice but to remain on 0.8.0 for now.