/usr/share/go-1.6/src/crypto/x509/ is in golang-1.6-src 1.6.1-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/go-1.6/src/crypto/x509/cert_pool.go
/usr/share/go-1.6/src/crypto/x509/example_test.go
/usr/share/go-1.6/src/crypto/x509/pem_decrypt.go
/usr/share/go-1.6/src/crypto/x509/pem_decrypt_test.go
/usr/share/go-1.6/src/crypto/x509/pkcs1.go
/usr/share/go-1.6/src/crypto/x509/pkcs8.go
/usr/share/go-1.6/src/crypto/x509/pkcs8_test.go
/usr/share/go-1.6/src/crypto/x509/pkix/
/usr/share/go-1.6/src/crypto/x509/pkix/pkix.go
/usr/share/go-1.6/src/crypto/x509/root.go
/usr/share/go-1.6/src/crypto/x509/root_bsd.go
/usr/share/go-1.6/src/crypto/x509/root_cgo_darwin.go
/usr/share/go-1.6/src/crypto/x509/root_darwin.go
/usr/share/go-1.6/src/crypto/x509/root_darwin_arm_gen.go
/usr/share/go-1.6/src/crypto/x509/root_darwin_armx.go
/usr/share/go-1.6/src/crypto/x509/root_darwin_test.go
/usr/share/go-1.6/src/crypto/x509/root_linux.go
/usr/share/go-1.6/src/crypto/x509/root_nacl.go
/usr/share/go-1.6/src/crypto/x509/root_nocgo_darwin.go
/usr/share/go-1.6/src/crypto/x509/root_plan9.go
/usr/share/go-1.6/src/crypto/x509/root_solaris.go
/usr/share/go-1.6/src/crypto/x509/root_unix.go
/usr/share/go-1.6/src/crypto/x509/root_windows.go
/usr/share/go-1.6/src/crypto/x509/sec1.go
/usr/share/go-1.6/src/crypto/x509/sec1_test.go
/usr/share/go-1.6/src/crypto/x509/sha2_windows_test.go
/usr/share/go-1.6/src/crypto/x509/verify.go
/usr/share/go-1.6/src/crypto/x509/verify_test.go
/usr/share/go-1.6/src/crypto/x509/x509.go
/usr/share/go-1.6/src/crypto/x509/x509_test.go
/usr/share/go-1.6/src/crypto/x509/x509_test_import.go