ProNovia development objects are generally created in the namespaces registered by ProNovia. There are two exceptions:
Authorization objects
Conversion exits
These objects are not namespace capable and can only be created in the customer namespaces. The authorization objects are stored in the ProNovia package /PRONOVIA/AUTH (up to UTI V9.3.3 in package Z_PRONOVIA_AUTH), the conversion exits can only be stored in a Z package: Z_PRONOVIA_J_CONV.
Details can be found in the following SAP Notes:
General information about namespaces: 104010
Authorization objects are described in detail in note 395083. The J areas specified under "Partner" are no longer possible. Thus, "Only identifiers beginning with Y or Z are available for object classes for both partners and customer projects".
Conversion exits are described directly in note 104010, see "...for a development in a namespace the letter 'J' should be chosen".