It seems fairly common to seex & xs in destructuring wherex is some arbitrary "thing" andxs is a sequence of such "things".

Yet the guide suggestsx andy are typically numbers.

Perhaps we can refine this:x andy are likely to be numbers when both are present, such as[x y] when a coordinate system is implied, butx standing alone tends to mean a arbitrary thing in a lot of cases, and especially when used withxs.

I don't have a specific suggestion to improve the wording but wanted to bounce this off the editorial team to see if we can come up with something better here?