ee3c8c01_CSS_Masking_Module_Level_1__Computed_value
[Name] mask-box-outset [Value] [ | ]{1,4} [Initial] 0 [Applies to] All elements. In SVG, it applies to container elements without the element and all graphics elements [Inh.] no [%ages] n/a [Media] visual [Animatable] no [Computed value] 
all s made absolute, otherwise as specified
CSS Masking Module Level 1
Computed value