I think I finally wrapped my head around how Hugo manages taxonomies.
I created my own taxonomy topic via the config.toml configuration
[taxonomies]
tags = 'tags'
topic = 'topic'
I also created a page layouts/-default_topics.html and, behold, it works! I get a page with all posts having a topic of “france” via http://localhost:1313/topic/france
There is one last thing I am missing: how are the three topic instances related: topic= and =topic in config.toml and the topic.html file. What drives what?
Your answer was perfect - thank you very much. It exactly answered my question (I still do not understand why this is so overengineered but there must be a reason for singular and plural forms).
I think that your answer should actually go into the docs - it is really precise.
Thank you but I still do not understand why not use only the singular form and have links such as https://example.org/author/(singular) even if there may be more than one. Is it just an aesthetical reason?
Sometimes you may want to render the plural form, and sometimes you may want to render the singular form. If you don’t think you will ever need to render the plural form of the taxonomy, use the same value for both in site config: