Magento – Add block in layout XML only for one store view

blockslayoutlayout-updatemagento-2.1xml

I have a Magento 2.1.x installation with two store views.
I would like to show a particular block in the footer only for one store view.

In Magento 1.9.x I would have done it in this way:

<STORE_storecode>
    <reference name="lorem_ipsum">
        <block type="..." />
    </reference>
</STORE_storecode>

How can I achieve that in Magento 2?

I'm not sure how you can do that in Magento 2, the cleanest way I can think of would be to :

You'll end up with the same effect, although it is more work than the method you mentioned for Magento 1.

You don't need the line

<?php echo $this->getChildHtml('favicon.extra') ?>

in head.phtml.
There is already this line that renders all child blocks

<?php echo $this->getChildHtml() ?>

[EDIT]
If for some reason you want to add the block in a specific place, you can use this:

<?php echo $this->getChildHtml('favicon.extra') ?>
<?php this->unsetChild('favicon.extra');?>

For Topmenu you should override \Magento\Theme\Block\Html\Topmenu:

protected function getCacheLifetime(){
    return null;
}