Don't remember which package depends on some libkerberos5. Assuming 
it's openssh or some component of pam. This raises a fundamental problem 
of distros. openssh and pam must be able to make use of as many 
authentication protocols as possible to cover the needs of all users. 
How can you reach this goal without linking them to the corresponding 
libraries? Maybe there's another method I don't know of? The alternative 
might be to have as many openssh or pam packages as there are 
combinations of the various available authentication systems, but it 
would lead to an enormous number of packages.

     The case of libsystemd0 is different. In an OS proposing systemd, 
it is normal to have libsystemd0, but not in a system which excludes it 
completely. Here is the choice Devuan faces: if systemd is installable, 
then many packages must depend on libsystemd, if no package depends on 
it, then systemd is not installable.

     Didier