RDA MARC records include the new 336/337/338 fields to record Content Type, Media Type and Carrier Type respectively. Each of these fields can use a term (like “text” in ǂa) and/or a shorter code (like “txt” in ǂb) for this information:
336 __ ǂa text ǂb txt ǂ2 rdacontent 337 __ ǂa unmediated ǂb n ǂ2 rdamedia 338 __ ǂa volume ǂb nc ǂ2 rdacarrier
If there are multiple types of content or carriers, the field should be repeated, possibly with a ǂ3 indicating which part you referring to:
336 __ ǂa performed music ǂb prm ǂ2 rdacontent 337 __ ǂa audio ǂb s ǂ2 rdamedia 338 __ ǂa audio disc ǂb sd ǂ2 rdacarrier 336 __ ǂa text ǂb txt ǂ2 rdacontent ǂ3 liner notes 337 __ ǂa unmediated ǂb n ǂ2 rdamedia ǂ3 liner notes 338 __ ǂa volume ǂb nc ǂ2 rdacarrier ǂ3 liner notes
Documentation varies on whether both ǂa and ǂb should be recorded in the same field. In practice, I commonly see both in the same field even in DLC records, but also see only the term used quite a bit.