This is is the link within the text:
<p class="text main">This is in-text.<sup><a id="textnote-02" href="endnotes.xhtml#endnote-02">2</a></sup></p>
This is the end note at the endnote page:
<p class="text endnotes" epub:type="endnote" role="doc-endnote" dir="rtl"><sup><a epub:type="referrer" role="doc-backlink" id="endnote-02" href="ch0002.xhtml#textnote-02">2</a></sup>This is the endnote.</p>
It works on Apple Books. However, on Google Books, it only works by taking me to endnotes page but it won't take me back to where I was.