If they are defined, they can override table-level settings.
const ASTPtr & left_in_operand, ContextPtr, const StorageMetadataPtr & metadata_snapshot) const
{
    /
    /
    /
    const auto * left_in_operand_tuple = left_in_operand->as<ASTFunction>();
    const auto & index_wrapper_factory = MergeTreeIndexFactory::instance();
    if (left_in_operand_tuple && left_in_operand_tuple->name == "tuple")
    {
        for (const auto & item : left_in_operand_tuple->arguments->children)
        {
            if (isPrimaryOrMinMaxKeyColumnPossiblyWrappedInFunctions(item, metadata_snapshot))
                return true;
            for (const auto & index : metadata_snapshot->getSecondaryIndices())
                if (index_wrapper_factory.get(index)->mayBenefitFromIndexForIn(item))
                    return true;
            for (const auto & projection : metadata_snapshot->getProjections())
            {
                if (projection.isPrimaryKeyColumnPossiblyWrappedInFunctions(item))
                    return true;
            }
        }
        /
        if (isPrimaryOrMinMaxKeyColumnPossiblyWrappedInFunctions(left_in_operand, metadata_snapshot))
            return true;
        for (const auto & projection : metadata_snapshot->getProjections())
        {
            if (projection.isPrimaryKeyColumnPossiblyWrappedInFunctions(left_in_operand))
                return true;
        }