lsb_release -a
--------------
Distributor ID:	Debian
Description:	Debian GNU/Linux 9.5 (stretch)
Release:	9.5
Codename:	stretch


apt-cache policy
----------------
Package files:
 100 /var/lib/dpkg/status
     release a=now
 500 http://ftp.debian.org/debian stable-updates/main amd64 Packages
     release o=Debian,a=stable-updates,n=stretch-updates,l=Debian,c=main,b=amd64
     origin ftp.debian.org
1000 http://security.debian.org stable/updates/main amd64 Packages
     release v=9,o=Debian,a=stable,n=stretch,l=Debian-Security,c=main,b=amd64
     origin security.debian.org
 995 http://ftp.debian.org/debian stable/main amd64 Packages
     release v=9.5,o=Debian,a=stable,n=stretch,l=Debian,c=main,b=amd64
     origin ftp.debian.org
Pinned packages: