Set footnotes to show by default

[Buhaj]

In last few books I read, I was only able to see footnotes when clicking on a hyperlink, see images 1 and 2.

I want to be able to set footnotes in such a way that they will be displayed on the same page by default. See image 3.

I have converted all ebooks with Calibre, to remove potential unnecessary formatting. In this chapter's xhtml file, the code is

<a id="footnote-226-backlink" class="footnote" href="naglowki_001_0014.xhtml#footnote-226">1</a><span class="reset">

The code on the file with the footnote content is

<div class="footnote1">
    <p class="calibre9"><a id="footnote-226" href="naglowki_001.xhtml#footnote-226-backlink" class="calibre14">1</a> Nick Miller, ‘<i class="calibre15">Why are they giving us the money?’ Behind China’s plans to ‘rescue’ a*decrepit rail link</i>, „The Sunday Morning Herald”, 20.07.2018, <a href="https://www.smh.com.au/world/europe/why-are-they-giving-us-the-money-behind-china-s-plans-to-rescue-a-decrepit-rail-link-20180606-p4zjwk.html" class="calibre14">https://www.smh.com.au/world/europe/why-are-they-giving-us-the-money-behind-china-s-plans-to-rescue-a-decrepit-rail-link-20180606-p4zjwk.html</a> (dostęp: 21.05.2022).</p>

Why are footnotes not displaying properly, and what custom code should I add to enable it (if possible)? Can it be Calibre that broke the formatting?

Also, in Calibre, I have EPUB output set to EPUB2. Shall I change it to EPUB3? I read in a post that default on-page footnotes require EPUB3, can this be true?

[Frenzie]

I read in a post that default on-page footnotes require EPUB3, can this be true?

By default yes, you'd need for example epub:type="footnote" on your footnote content. I'm not really sure why you didn't try it already?

Enabling classic classname footnotes does implement .footnote but not .footnote1. Though which process did this classname come into existence? Converted from what to what?