maskBorderSlice
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Syntax: <number-percentage>{1,4} fill?
Initial value: 0
| Chrome | Firefox | Safari | Edge | IE |
| :------------------------------------: | :-----: | :----------------------------------: | :-------------------------------------: | :-: |
| 1 _(-webkit-mask-box-image-slice)_ | No | 17.2 | 79 _(-webkit-mask-box-image-slice)_ | No |
| | | 3.1 _(-webkit-mask-box-image-slice)_ | | |Content copied to clipboard