Questions about apt-cache showpkg

Question

when I enter

$ apt-cache showpkg gnome-devel

in my terminal, I get :

Package: gnome-devel
Versions: 
1:3.0+6ubuntu4 (/var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_quantal_universe_binary-amd64_Packages)
Description Language: 
    File: /var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_quantal_universe_binary-amd64_Packages
MD5: 4682dc9d7825daf220363435b46d793b
 Description Language: en
File:               /var/lib/apt/lists/fr.archive.ubuntu.com_ubuntu_dists_quantal_universe_i18n_Translation-en
                  MD5: 4682dc9d7825daf220363435b46d793b


Reverse Depends: 
Dependencies: 
1:3.0+6ubuntu4 - anjuta (2 2:3.0) anjuta-extras (2 3.0) devhelp (2 3.0) glade (2 3.10) gnome-devel-docs (2 3.0) gnome-platform-devel (0 (null)) 
Provides: 
1:3.0+6ubuntu4 - 
Reverse Provides:

But there are some details that I don't understand.

What does "1:3.0+6ubuntu4" mean here? Is it the minimum Ubuntu version for this package ?
What does (0 (null)) mean for the dependency package gnome-platform-devel? I think it means this package is just recommended : am I right ?
In ajunta (2 2:3.0) : what does the leading "2" in version number (2 2:3.0) mean? I think that it is for ">=" : am I right ?

apt-cache search does not give me required versions numbers. Man apt-cache does not provides enough information for (0 (null)) — loloof64, May 06 '13 at 08:56

score 2 · Accepted Answer · answered May 06 '13 at 09:28

Finally aptitude helps me

$ LANG=C aptitude show gnome-devel
Package: gnome-devel                     
State: not installed
Version: 1:3.0+6ubuntu4
Priority: optional
Section: universe/devel
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Architecture: all
Uncompressed Size: 43.0 k
Depends: anjuta (>= 2:3.0), anjuta-extras (>= 3.0), devhelp (>= 3.0), glade (>=
     3.10), gnome-devel-docs (>= 3.0)
Recommends: gnome-platform-devel
Description: The GNOME Desktop Environment -- development tools
 These are the development tools of the GNOME Desktop environment, an intuitive
 and attractive desktop. 

 This meta-package depends on a recommended set of applications to develop new
 programs for GNOME.

score 1 · Answer 2 · answered Jul 24 '16 at 16:43

To add to this in case anyone is trying to read it straight from apt-cache showpkg I found that the meanings of the values before the version number are as follows:

NoOp=0,LessEq=0x1,GreaterEq=0x2,Less=0x3,
Greater=0x4,Equals=0x5,NotEquals=0x6

as found in the source code here on line 156 at the time of writing. So the leading 2 means greater than or equal to, as the original answer stated.

Questions about apt-cache showpkg

2 Answers2