Did you install anything on Cydia that mentions it? I remember there being something on Cydia that just adds the icon but not the actual app.I randomly just found Passbook on an extra page on my home screen. When I click it, it flashes black and goes back to the home screen. Why is it there? How can I remove it?
I would have said it's that but if not it then I don't know sorry.Just rechecked. Nothing. At most, I installed an iOS 6 theme but I checked the contents and nothing would make it show up.
Edit: I actually just turned off the theme, and it's still there.
What is the modification and created date of the contents of the app? This is definitely a jaiilbreak thing. Apple cannot write to the root partition with anything short of a full blown over the air update or iTunes update/restore.