ee3c8c01_CSS_Masking_Module_Level_1__Computed_value
[Name] mask-size [Value] # [Initial] border-box [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] as repeatable list of simple list of length, percentage, or calc (This means keyword values are not animatable.) [Computed value] 
as specified, but with lengths made absolute
CSS Masking Module Level 1
Computed value