Package xerrors implements functions to manipulate errors. This package is based on the Go 2 proposal for error values: https://go.dev/design/29934-error-values These functions were incorporated into the standard library's errors package in Go 1.13: - Is - As - Unwrap Also, Errorf's %w verb was incorporated into fmt.Errorf. No other features of this package were included in Go 1.13, and at present there are no plans to include any of them.