Libzypp/Solver/UseCase/Obsolete
From openSUSE
Obsolete represents a renaming of a resolvable. E.g. foo_new obsoletes foo_old. That means that foo_old will be deleted if foo_new will be installed.
This behaviour will be represented by a conflict in the solver (caused by the obsolete). So foo_new conflicts with foo_old.
For more information have a look to QueueItemConflict.

