Which ML model does Apple use to generate stickers in iOS 17?

I've experimented with semantic segmentation models like DeeplabV3 on Core ML to try to generate stickers from images. However, the results from DeeplabV3 don't look nearly as clean and accurate as the stickers generated in the Messages app on iOS 17.

On the Apple Machine Learning models page, DeeplabV3 is the only image segmentation model they offer. However, it seems they must be using a more advanced model to achieve such high quality sticker generation directly from the camera roll. …

app apple apple machine learning computervision core deeplabv3 generate generated images ios ios 17 look machine machine learning machine learning models messages segmentation semantic