Details of a package occurrence.
This represents a particular channel of distribution for a given package.
E.g., Debian’s jessie-backports dpkg mirror.
This represents how a particular software package may be installed on a
system.
An occurrence of a particular package installation found within a system’s
filesystem. E.g., glibc was found in /var/lib/dpkg/status
.
This represents a particular package that is distributed over various
channels. E.g., glibc (aka libc6) is distributed by many, at various
versions.
Version contains structured information about the version of a package.