I think you’re missing two key facts from Page Resources.
any page, including sections and the home page can have resources so the .Resources method always make sense.
A content directory will only become a page bundle if one of its md file is named index.md. This is how Hugo can know which md file is the Page itself, and which md files are just resources of given Page.
On top of the doc, you could check this blog post.
@pointyfar I’ve managed to use a headless bundle as repository for multiple resources that I can use from other pages, thanks
@regis: I think I understand what .Resources are, but I don’t understand what the “resources” variable accomplishes in the front matter, especially if “src” can’t point outside the current page bundle. But it doesn’t matter.