/usr/share/go-1.8/src/strings/ is in golang-1.8-src 1.8.3-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/go-1.8/src/strings/compare.go
/usr/share/go-1.8/src/strings/compare_test.go
/usr/share/go-1.8/src/strings/example_test.go
/usr/share/go-1.8/src/strings/export_test.go
/usr/share/go-1.8/src/strings/reader.go
/usr/share/go-1.8/src/strings/reader_test.go
/usr/share/go-1.8/src/strings/replace.go
/usr/share/go-1.8/src/strings/replace_test.go
/usr/share/go-1.8/src/strings/search.go
/usr/share/go-1.8/src/strings/search_test.go
/usr/share/go-1.8/src/strings/strings.go
/usr/share/go-1.8/src/strings/strings.s
/usr/share/go-1.8/src/strings/strings_amd64.go
/usr/share/go-1.8/src/strings/strings_decl.go
/usr/share/go-1.8/src/strings/strings_generic.go
/usr/share/go-1.8/src/strings/strings_s390x.go
/usr/share/go-1.8/src/strings/strings_test.go