deriv LSK ETT STT aSTA ALPH OLDHOMEPAGE NEWHOMEPAGE
According to current custom, you always say duSSantaH, but you always type it as duHSanta. (According to vAzari, you MAY say duH + Santa, but no one does that.)
Now, Houston, we have a problem. When sorting words alphabetically, duH दुः comes before dur दुर् and dur दुर् before duS दुष्. Then, should we put duSSanta दुःषन्त after durmanas दुर्मनस् or before it?
The answer to this question is obvious if you have been educated according to Western culture: "who cares how the heck it's said? Just trust the spelling, as it's spelled with duH it must go before dur".
The answer to this question is also obvious if you got your education at a gurukula गुरुकुल. "Who cares how the heck it's spelled? /pANini doesn't mention spelling rules a single time. We just spell duHS for duSS because we're lazy. Everybody says duSSanta, so put it after dur or people will look for it in the wrong place".
So it's placed in the list as if it were duSSanta, but it appears in that place spelled as duHSanta.
The people who write the Sanskrit version of wikipedia got their education under the Western system, and tend to assume that their readers are too ignorant to know that duHS should be pronounced duSS, so you may expect duHSanta to be sorted western-style in the future.
BTW, see pronunciation of jJ.