Trinacria is a vanilla kingdom, but it's only available in later starts after Sicilian Vespers, when Sicily is divided between Naples and Trinacria.Sorry, I meant "Trinacria" and the CoA for the title – is this just vanilla but you customised your realm name? Trinacria is normally Sicily, right?
The mods in use are probably Patrum Scuta (the new CoA for both dynasties and titles) and Bigger Interface. There might be others.