[Scribus] What is an S font?

[Brian Astill]

In Scribus Preferences, all but three of my installed fonts are 
marked with the Tt truetype symbol.  Those fonts are  accessible.

The remaining three - Gargi 1.7, Comix and Fritz - are marked with 
an S and are NOT accessible.  I can see no difference in type, 
location, permissions or ownership of these three compared to the 
other, available, fonts.

Advice, anyone?

-- 
Regards,
Brian