IV.16. 505 : Contents Note

505s can be either basic (second indicator blank), with all contents in a single subfield $$a, or enhanced (second indicator 0), with contents encoded using subfields $$t, $$r, and $$g. When producing original records, create enhanced 505 notes whenever possible. Basic 505 notes are abundant in existing records; there is no obligation to enhance them.

Catalogers may encounter older records in which the 505 is divided into two or more fields, with first indicator 0 for the first 505 field, and first indicator 8 for the subsequent 505 field(s). This practice owed to a 2000-character limit per MARC field in Aleph, Alma's predecessor.  In Alma, no such limit applies, but since both Alma analytics and HART have searching limits, it is recommended to retain this limit (and NB: It has been noted in Alma that a long list of contents -- more than 15 titles? -- in a single 505 field automatically generates extra $$a, creating an error message when attempting to save the record; this can be resolved by simply balancing the fields properly). 

Supplied information should be in the language of the manifestation.  See RDA 2.3.2.11: "Use the language and script appropriate to the content of the resource being described, except where instructed to use specific terminology"; and the LC-PCC PS Alternative: "Devise a title in a language and script preferred by the agency preparing the description." The Rare Book Section interprets these instructions to mean that the language of the manifestation is preferable.