Well, the original El País article seems to be correct to me, aside from the possible mistake of including "ll" in the extra letters - not sure if that is the case. If they were to do that, they might also include the "ch" character as well.
The guy writing the vivirlatino article obviously gets himself a little confused, saying "Imagine the value of a site called "niños.com" (which when you type into a browser now, redirects to
http://xn--nios-hqa.com/) to a baby products company". Yes, I'm sure Laura Snow agrees!
Ah. Here's some info direct from red.es...
http://www.mityc.es/es-ES/Servicios/...ltilinguis.htm
They give the mystery extra as "l•l (l geminada del catalán)" = "twinned L". I think whoever generated that sentence didn't do it in UTF8 and when it converted over for the website, it screwed up.
On further investigation, the Unicode character they're referring to is ŀ = "LATIN SMALL LETTER L WITH MIDDLE DOT" = Catalan legacy compatibility character for ISO 6937