Possible typo (PTSN) in desktop search terms

In data/sm.puri.Calls-daemon.desktop.in and data/sm.puri.Calls.desktop.in are desktop search terms:

Telephone;Call;Phone;Dial;Dialer;PTSN;

Here I wonder if PTSN is a typo. Wikipedia only lists PSTN: https://en.wikipedia.org/wiki/Public_switched_telephone_network