Link: https://drafts.csswg.org/css-scroll-snap/

According to the spec, values of scroll-snap-type follow the format none | [ x | y | block | inline | both ] [ mandatory | proximity ]?, which I understand to mean that values like x mandatory or block are valid, but mandatory alone is not. However, in Section 2 (Motivating Examples) I noticed that scroll-snap-type: mandatory; and scroll-snap-type: proximity; are utilized. Is the intention to make those valid values for scroll-snap-type?

If they are, would it make sense to make the default axis type both when only proximity or mandatory are specified?