Gentlemen, on the above URL let's examine the links for e.g., "[+] Buses by continent (6 C)"
<span class="CategoryTreeBullet"><a href= "/wiki/Category:Buses_by_continent" class="CategoryTreeToggle"
title="expand">[<b>+</b>]</a></span> <a class="CategoryTreeLabel
CategoryTreeLabelNs14 CategoryTreeLabelCategory" href= "/wiki/Category:Buses_by_continent">Buses by continent</a> <span title="contains 6 subcategories, 0 pages, and 0 files">(6 C)</span>
The problem is, if the user is using a text browser or any other
he just ends up with pairs of the same hyperlink.
Therefore TABing through a page, he has to hit twice as many tabs to
get to where he wants, to step over what are now pairs of the same
who don't. (Accessibility impact.)
One approach would be to rewrite so the whole first link only appears
Anyway, all I know is please test these things in text browsers next