Sorry, we do know, it's for serious breaches.
I'm presuming that they've told City but then again, UEFA are coming across (again) as totally inept so perhaps they didn't.
Edit: It's possible that it has been posted on here but the damned thread's moving too fast, we need a summary, preferably stickied to the top of the thread.
Updated for you but sorry don't know how to make it a stickie
UEFA investigatory chamber: "have you seen these leaked emails?, fucking hell we might have something here, lets open an investigation"
UEFA teaboy: "you realise those were stolen, are out of context and oh the statute limitations runs out any day now?"
UEFA investigatory chamber: "shit, shit, shit, kick it upstairs now !, oh and don't forget to gob off to your mates in the press, we will have these bastards"
City: "errm, what are you investigating us about exactly?"
UEFA investigatory chamber: ………
City: "errm, what are you investigating us about exactly?"
City: "and would you please respect your own confidentiality rules whilst you decide?"
UEFA adjudicatory chamber (to the investigatory chamber): "you dickheads, where is the investigation report?"
UEFA investigatory chamber: ………
UEFA investigatory chamber: "here have our scope document instead"
City: "errm that's not due process"
UEFA adjudicatory chamber: "never mind that, will you just pay a fine/accept a ban please?"
City: "NO, fuck off !"
City: "and would you PLEASE respect your own confidentiality rules?"
UEFA adjudicatory chamber: "never, how dare you accuse.... "
City: > CAS
CAS: "UEFA you are a bunch of fucking clowns, go away and think about this properly"
UEFA: "Shit, shit shit - what do we do now ?"
UEFA: "errmmm"
UEFA: "fuck it, throw the book at them"
UEFA: "you sure?"
UEFA: "no, but do it anyway"
City: "sigh........."