Order "0" is seen as "1"

[Eddcapone]

You wrote Any tags without an explicit order will come as they appear normally (effectively treated like they have an order of 1).

So I added a script with order 0, so that it gets ordered to the very top:

<css src="css/bootstrap.min.css" order="0"/>

But it is not.

I also tried 10 but then it gets ordererd at the bottom.

[Eddcapone]

I figured out that if you set the order to 0 it will be seen as "1" in
View\Page\Config\Renderer.php in Method _afterRenderAssets.

It goes in if(!isset($this->_aAssetOrder[$sSearch]) || $this->_aAssetOrder[$sSearch] == 1) {

[Eddcapone]

We could workaround it by overriding $oFile->setOrder(1); to $oFile->setOrder(10); in View\Asset\PropertyGroup.php and then we can use 1 instead of 0. But this might break some shops, since people who already set their order and update the extension will face bugs because the order gets confused again.