I don’t understand what should go in that necessary front matter. I’m so used to .md files I had not registered frontmatters applied to all files.
if my file.html is under /content/essai/, how do I refer to it from the frontmatter, or do I also need an index.md ? I read What is a better way to include a full external html page and its resources into blog - #2 by RickCogley but option 2 is the only I didn’t understand.