What color model does WebP implement?

Does it natively support sRGB? When you load and save image data using the libwebp API, do you assume linear or sRGB encoded data? Is there a way to indicate you’d like sRGB data?

Does it natively support associated alpha? When you load and save image data using the libwepb API, do you assume unassociated or associated alpha? e.g. if I have a pixel buffer containing associated alpha, do I need to convert it to unassociated alpha before saving with libwebp?