Originally reported here: https://pl.wikipedia.org/wiki/Wikipedia:Kawiarenka/Kwestie_techniczne#c-MarMi_wiki-20230301170000-Uwaga_w_VE
For example, this reference, rendered as [f]: https://pl.wikipedia.org/w/index.php?title=Nowa_Gwinea&oldid=69752489#cite_ref-73
(which is achieved with local customizations: https://pl.wikipedia.org/w/index.php?title=MediaWiki:Common.css&oldid=69734983#L-1067 and https://pl.wikipedia.org/wiki/MediaWiki:Cite_link_label_group-uwaga)
When editing in visual editor, it has a focusable highlight that is bigger than the reference itself:
Because internally we render the text [uwaga 6] in the reference node, to improve behavior around text selection (CSS generated content is not selectable in browsers, if we don't render real content, the browser's selected text background will have gaps where references are):
