Ironically, the very example the author uses for annotations doesn't work properly for me : on touchscreen Android Firefox I get a link instead of a popup when

Ironically, the very example the author uses for annotations doesn't work properly for me : on touchscreen Android Firefox I get a link instead of a popup when press-holding. And aren't annotations (and references) already part of the EPUB specification, and probably even the HTML specification ?!? Finally, I disagree with the press-and-hold for popup being better than the usual practice of hyperlink anchors, IMHO their jumping around is much less disruptive. (As long as the reader's "return" function is working properly, and/or - for the bijective ones - they provide a "back" hyperlink.)