`appearance: none` triggers a warning even though it's supported

> Unexpected browser feature "css-appearance" is not supported by IE 11 and only partially
supported by Firefox 52,54, Chrome 49,58,59, Safari 10.1, Opera 46, iOS Safari 10.3, Chrome for
Android 59, Samsung Internet 4

`appearance` is not supported, but it's oftenly used as `-webkit-appearance: none` to disable browser's styles.

Is there any way to ignore `appearance` with this particular value `none`, but warn on other values?