Hello there and welcome! These tags are on a POI that features in a scientific paper: ref:Wenger should be self-explaining - it is a reference to the name of the author of the paper and cites/quotes a shorthand to the resource there.

ele:Wenger I made up, because the ele given in the paper seems wrong to me, both from contour lines and from GPS readings, so I suffixed that during my edit to have it nevertheless in the data. Perhaps better ele:ref:Wenger1977 would be less confusing?

BTW: How did you spot that?