kotlin-fork/idea/resources/META-INF/kotlinx-serialization.xml

<idea-plugin>
    <extensions defaultExtensionNs="org.jetbrains.kotlin">
        <expressionCodegenExtension implementation="org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDECodegenExtension"/>
        <syntheticResolveExtension implementation="org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDEResolveExtension"/>
        <jsSyntheticTranslateExtension implementation="org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDEJsExtension"/>
        <irGenerationExtension implementation="org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDEIrExtension"/>
        <storageComponentContainerContributor implementation="org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDEContainerContributor"/>
    </extensions>
</idea-plugin>