Why is HorizontalStack and VerticalStack not available in Polaris anymore?

[nicklocicero]

You can see here, that the same is true for HorizontalStack, there is no export available for VerticalStack:

HorizontalStack:

When I click VerticalStack in the Build an App tutorial documentation, it takes me to BlockStack documentation.

When I click HorizontalStack on in the Build an App tutorial documentation, it takes me to InlineStack documentation.

Where did HorizontalStack and VerticalStack go and how can I find out about big changes like this?