$ apt-cache policy wine
wine:
  Installed: (none)
  Candidate: 1.4.1-4
  Version table:
     1.4.1-4 0
        500 http://ftp.pt.debian.org/debian/ wheezy/main amd64 Packages
$ apt-cache policy libxcb-glx0
libxcb-glx0:
  Installed: 1.10-3~bpo70+1
  Candidate: 1.10-3~bpo70+1
  Version table:
 *** 1.10-3~bpo70+1 0
        100 http://ftp.pt.debian.org/debian/ wheezy-backports/main amd64 Packages
        100 /var/lib/dpkg/status
     1.8.1-2+deb7u1 0
        500 http://ftp.pt.debian.org/debian/ wheezy/main amd64 Packages
        500 http://security.debian.org/ wheezy/updates/main amd64 Packages