# apt-cache policy firefox firefox: Installed: 1.99+2.0rc2+dfsg-0ubuntu1 Candidate: 1.99+2.0rc2+dfsg-0ubuntu1
# apt-cache policy firefox 0rc2+dfsg- 0ubuntu1 0rc2+dfsg- 0ubuntu1
firefox:
Installed: 1.99+2.
Candidate: 1.99+2.