Arkadaşlar aşağıdaki CSS level 2.1 tarama sonuçları hata satırlarının anlamı nedir acaba ?

Property overflow-y doesn't exist in CSS level 2.1 but exists in [css3] : hidden
Property -moz-background-clip doesn't exist : -moz-initial
Property -moz-background-origin doesn't exist : -moz-initial
Property -moz-background-inline-policy doesn't exist : -moz-initial
Parse Error title