Item records should have the x subfield - also known as the private note. This is missing when adding or editing an item to a record.
This is an enhancement request, and one that could be better described IMO. The Koha item record does not have a non-private notes field, just a general notes field. Whether or not it gets mapped to 952$x in the MARC framework is not actually relevant. Extended this a bit further, another thing that could be done would be to support more than one note for per item; in other words, rather than just have a general notes field, or even two notes fields (public and private), a better enhancement might be to support allowing an arbitrary number of notes to be attached to an item record.
Sorry it was poorly worded, I had a cataloger ask where the $x subfield was in the item record. I know that on the Koha to Marc mapping : /cgi-bin/koha/admin/koha2marclinks.pl after choosing 'items' there is an $x subfield already listed - so Koha knows about it - it's just not on the add or edit item record. Or I'm just making the wrong assumption.
This isn't an issue in the current HEAD - the field is there on the item record. Closing.