golang-golang-x-xerrors-dev 0.0~git20191204.9bdfabe-1 (s390x binary) in ubuntu focal

 This package contains the transition packages for the new Go 1.13
 error values.
 .
 Most of the functions and types in this package will be incorporated into the
 standard library's errors package in Go 1.13; the behavior of this package's
 Errorf function will be incorporated into the standard library's fmt.Errorf.
 Use this package to get equivalent behavior in all supported Go versions.