Thank you for doing the investigation. I was hoping to find time to look at it, but until the election, I’m going to have little time, unless there are some boring meetings at work. ;-).
But if you must, set up a way to find it, such as have it tagged with the plugin it came from etc…
Special note
Systems tiddlers can have captions and appear in lists as a regular tiddler, without the $:/ prefix visible and a designer can do things like have system tiddlers use an alternative title when being viewed?
A regular tiddler can transclude a shadows or system tiddler thus have the content stored in the shadow or system tiddler visible.
So things are not always as they seem.