I don't think so, it may have been a removed pirate ability. Never got errors from it before.

Edit: Actually I don't see a file of that name in any version. Maybe its a Rebellion entity file name that snuck in there?

There is that file listed at the bottom of the manifest but if you do a notrpad++ count, the count of the manifest is off by -1 so the manifest does not count or load it.

Are you using a modded manifest? Hell I might have even fixed the count when I uploaded my reference files but I dont think so. It should not spit an error with the count -1 from the actual count. 

I took it out of the manifest so that when I add entities and do the notepad++ count, the count is not buggered.

Doubt it. Just a redundant manifest line. They were probably playing around with that entity and decided to scrub it.

Also they like to keep the m0dders punching the screen tracking their errors. 

Take a look for yourself, its in the unmodded Diplomacy entity.manifest file.

Its not the first time they've left a small bit of Rebellion content into the data files in Diplomacy.