There are two items to be enabled to get this working:
1) A template; you have that covered!
There seem to be some confusion with the above, so I'll take 2) in detail.
You can define
outputs at two levels; I will use your concrete use case (the section listing):
section = ["HTML", "RSS", "JSON"]
Note that if a page
Kind is not in the list above, it will get the "old default" output format, i.e. what Hugo had before 0.20, i.e. HTML and RSS. This also means that if you do put a
Kind in there, you will have to supply the full list.
In the example above I say that for the section list I want to output HTML, RSS and JSON. The other kinds of pages, i.e. home page, regular pages etc., will get the "Hugo defaults".
If you want some special output for 1 page only, this can also be defined (or overridden) in the page frontmatter. In your case, you could create
In the YAML frontmatter.