The package golang-github-spf13-viper 0.0~git20160420.0.f904a17-1 has been added to kali-rolling. It has been imported from Debian: https://tracker.debian.org/pkg/golang-github-spf13-viper -- More information about golang-github-spf13-viper: http://pkg.kali.org/pkg/golang-github-spf13-viper