KvadrantScrim

fun KvadrantScrim(modifier: Modifier = Modifier, content: @Composable () -> Unit = {})

Dims what is behind something, at PhoneSemitransparentColor.

Not what a message box uses, despite the name it used to carry here: that one dims with 60% of the theme background, so it is a white veil in the light theme, and it now lives inside KvadrantMessageBox where the original keeps it. This is the token brush, for whatever else wants it.