Geezer's link mentions that
"At Zurich Airport, "UNCAT" has been employed for the ILS runway 28 due to physical characteristics of the aerodrome infrastructure (e.g. runway strip width, distance from TWY A and B to runway centre line, location of runway holding positions) and obstacle clearance after passing the approach minimum down to the landing threshold 28 (dimension and slope of the Annex 14 obstacle limitation surfaces)."
Does the chart specify what the deviation from a standard ICAO ils is? After all, in minimum visibility, it would be nice to know where and how high these obstacles are. And whether the "uncat" designation due to infrastructure is simply because a taxiway is closer to the runway that permitted....