Retrieve Taxonomy and Sitemap via Delivery API (Workaround)
As for now Delivery API doesn't have any support for Taxonomy or Sitemap, but it's on our roadmap, no worries!
Workaround at the moment is to create a special content item called, e.g. Taxonomy_group_XY, then assign all the taxonomy terms within a specific taxonomy group to this item. When you will get this item via Delivery API, it will contain all the taxonomy terms, so you can use them for filtering or so. The same approach can be used to retrieve the whole Sitemap.
If you're going to use this workaround, please let us know about your use-case. When and why would this kind of API be beneficial for you?