where is the "extra-rounded" in CornersDotOptions?

[DancingWhiteFire]

I' m a developer.
so I love using qr-code-styling but why can't I use the type "extra-rounded" in CornersDotOptions?
dotsOptions: {
type: 'dots'
},
cornersSquareOptions: {
type: 'extra-rounded'
},
cornersDotOptions: {
type: 'dot', // not allowed "extra-rounded"
},