/etc/xdg/libksieve.categories is in libkf5ksieve-data 4:17.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | org.kde.pim.libksieve kdepim (libksieve)
org.kde.pim.kmanagersieve kdepim (libksieve manager)
org.kde.pim.sieve kioslave (sieve)
|