201912 – This block is currently only available in the Gutenberg plugin and has not yet been rolled into WP core.
I was hoping that this block would also be able to create a TOC for a page based on headings in the page itself (anchor links). Clearly, that’s a separate item — this block is meant to move toward using blocks for all page and interface building needs (including the top menu).
So… with that in mind, I think this block also needs to have a vertical orientation option, for appearing in sidebars. I’m not loving the options, at the moment.
An example of a default navigation block with all top-level pages:
Another test (dark style)
None of the colour styles I’ve tried actually appear to do anything. Not sure if it has to do with this theme or not.