libpam-systemd 219-7ubuntu4.1 (amd64 binary) in ubuntu vivid

 systemd is a system and service manager for Linux. It provides aggressive
 parallelization capabilities, uses socket and D-Bus activation for starting
 services, offers on-demand starting of daemons, keeps track of processes
 using Linux control groups, supports snapshotting and restoring of the system
 state, maintains mount and automount points and implements an elaborate
 transactional dependency-based service control logic.
 .
 systemd is compatible with SysV and LSB init scripts and can work as a
 drop-in replacement for sysvinit.
 .
 This package contains the PAM module which registers user sessions in
 the systemd control group hierarchy.
 .
 If in doubt, do install this package.
 .
 Packages that depend on logind functionality need to depend on libpam-systemd.