reading through some previous messages and I can hide the warning by adding a lint with ```<?xml ...

# serialization

[Fred Bowker]

reading through some previous messages and I can hide the warning by adding a lint with

<?xml version="1.0" encoding="UTF-8"?>
<lint>
    <issue id="UnsafeOptInUsageError" severity="ignore">
        <option name="opt-in" value="kotlinx.serialization.InternalSerializationApi" />
    </issue>
</lint>

but not sure why this is necessary, or whether this is an issue with intellij