|For RIFA made capacitors like this one, the rupture is accompanied by smoke and a strong foul odour.
The odour will persist until the capacitor is removed. The capacitor contains fluid, which may leak out.
Do not touch the fluid (it may be carcinogenic, or otherwise toxic).
The "X" in "0,1µF@X" probably indicates that this capacitor is of class X (expected because it sits between line and neutral).