3.5. Dependencies
Every package must specify the dependency information about other packages that are required for the first to work correctly.
For example, a dependency entry must be provided for any shared libraries required by a dynamically-linked executable binary in a package.
Packages are not required to declare any dependencies they have on other packages which are marked Essential
(see below), and should not do so unless they depend on a particular version of that package. 4
Sometimes, unpacking one package requires that another package be first unpacked and configured. In this case, the depending package must specify this dependency in the Pre-Depends
control field.
You should not specify a Pre-Depends
entry for a package before this has been discussed on the debian-devel
mailing list and a consensus about doing that has been reached.
The format of the package interrelationship control fields is described in Declaring relationships between packages.