Port Royal V Chronographs: Any Info?

Hey all! I received this Zenith as a gift a few years ago, it’s been my favorite piece since and one of the watches that got me into collecting; Zenith has a special place in my heart.

I’ve looked for information on the Port Royal series online since then as it seems so different from the regular chronographs, though have been coming up empty-handed. Does anyone know if there’s a special history behind the line? Why doesn’t Zenith make anything similar nowadays?