$5 - Githubissues

Preliminary research:
Control Subfields general definition:

$5 Institution to which field applies MARC code of the institution or organization that holds the copy to which the data in the field applies. Data in the field may not apply to the universal description of the item or may apply universally to the item but be of interest only to the location cited.

I went through all the tags and these are the MARC fields i found with $5 defined.

0xx:

026 - Fingerprint Identifier (R) Used to assist in the identification of antiquarian books by recording information comprising groups of characters taken from specified positions on specified pages of the book, in accordance with the principles laid down in various published guidelines.
037 - Source of Acquisition (R) Source of acquisition information for the item or its reproduction.

1xx: $5 is not defined for any of the 1xx fields

2xx:

246 - Varying Form of Title (R) Varying forms of the title appearing on different parts of an item or a portion of the title proper, or an alternative form of the title when the form differs substantially from the title statement in field 245 and if they contribute to the further identification of the item.

3xx: $5 is not defined for any of the 3xx fields.

4xx: $5 is not defined for 490, the only currently valid 4xx field.

5xx:

500 - General Note (R) General information for which a specialized 5XX note field has not been defined.
501 - With Note (R) Note indicating that more than one bibliographical work is contained in the physical item at the time of publishing, release, issue, or execution. The works that are contained in the item usually have distinctive titles and lack a collective title.
506 - Restrictions on Access Note (R) Information about restrictions imposed on access to the described materials.
533 - Reproduction Note (R) Descriptive data for a reproduction of an original item when the main portion of the bibliographic record describes the original item and the data differ.
538 - System Details Note (R) Technical information about an item, such as the presence or absence of certain kinds of codes; or the physical characteristics of a computer file, such as recording densities, parity, blocking factors, mode of access, software programming language, computer requirements, peripheral requirements, trade name or recording systems, number of lines of resolution, and modulation frequency. For sound and videorecordings, information about the trade name or recording system(s) (e.g., VHS), modulation frequency and number of lines of resolution may be included. Links to technical details relating to digital resources may also be recorded.
540 - Terms Governing Use and Reproduction Note (R) Terms governing the use of the materials after access has been provided. The field includes, but is not limited to, copyrights, film rights, trade restrictions, etc. that restrict the right to reproduce, exhibit, fictionalize, quote, etc.
541 - Immediate Source of Acquisition Note (R) Information about the immediate source of acquisition of the described materials and is used primarily with original or historical items, or other archival collections.
561 - Ownership and Custodial History (R) Copy-specific field that contains information concerning the ownership and custodial history of the described materials from the time of their creation to the time of their accessioning, including the time at which individual items or groups of items were first brought together in their current arrangement or collation.
562 - Copy and Version Identification Note (R) Information that distinguishes the copy(s) or version(s) of materials when more than one copy or version exists or could exist.
563 - Binding Information (R) Binding information intended primarily for use with antiquarian materials, rare books and other special collections.
583 - Action Note (R) Information about processing, reference, and preservation actions.
584 - Accumulation and Frequency of Use Note (R) Measurements of and information about the rates of accumulation (for continuing, open-ended accessions) and/or the rate of reference use of the described materials.
585 - Exhibitions Note (R) Copy-specific field that contains a note which cites exhibitions where the material described has been shown.
588 - Source of Description Note (R) Information used for tracking and controlling the metadata contained in the record. It includes general and specific source of description notes that are especially of interest to other catalogers.

6xx:

655 - Index Term-Genre/Form (R) Terms indicating the genre, form, and/or physical characteristics of the materials being described. A genre term designates the style or technique of the intellectual content of textual materials or, for graphic materials, aspects such as vantage point, intended purpose, characteristics of the creator, publication status, or method of representation. A form term designates historically and functionally specific kinds of materials distinguished by their physical character, the subject of their intellectual content, or the order of information within them. Physical characteristic terms designate historically and functionally specific kinds of materials as distinguished by an examination of their physical character, subject of their intellectual content, or the order of information with them.

7xx:

700 - Added Entry-Personal Name (R) Added entry in which the entry element is a personal name.
710 - Added Entry-Corporate Name (R) Added entry in which the entry element is a corporate name.
711 - Added Entry-Meeting Name (R) Added entry in which the entry element is a meeting name.
730 - Added Entry-Uniform Title (R) Uniform title, a related or an analytical title that is controlled by an authority file or list, used as an added entry.
740 - Added Entry-Uncontrolled Related/Analytical Title (R) Added entries for related or analytical titles that are not controlled through an authority file or list. (If related or analytical titles are controlled by an authority file, use field 730 (Added entry - uniform title)).
758 - Resource Identifier (R) An identifier for a resource that is either the resource described in the bibliographic record or a resource to which it is related. Resources thus identified may include, but are not limited to, FRBR works, expressions, manifestations, and items. The field does not prescribe a particular content standard or data model.

8xx:

800 - Series Added Entry-Personal Name (R) Author/title series added entry in which the author portion is a personal name.
810 - Series Added Entry-Corporate Name (R) Author/title series added entry in which the author portion is a corporate name.
811 - Series Added Entry-Meeting Name (R) Author/title series added entry in which the author portion is a meeting name or conference name
830 - Series Added Entry-Uniform Title (R) Series added entry consisting of a series title alone.

The section from 840 up to 890 contains a number of fields documented in MARC Format for Holdings; I checked the ones not documented in the Bibliographic format in the holdings format, which also has $5 defined.

843 - (Holdings) Reproduction Note (R) Description of an item that is a reproduction of original materials. Used when an institution chooses to have the main portion of the bibliographic record description reflect the original and the notes in field 843 reflect information about the copy.
845 - (Holdings) Terms Governing Use and Reproduction Note (R) Terms governing the use and reproduction of a bibliographic item when the holding organization will lend (008/20, Lending policy, code a) and reproduce (008/21, Reproduction policy, code a) the item.
880 - Alternate Graphic Representation (R) Fully content-designated representation, in a different script, of another field in the same record. Field 880 is linked to the associated regular field by subfield $6 (Linkage). A subfield $6 in the associated field also links that field to the 880 field. The data in field 880 may be in more than one script.
(Note that any subfield from a-z and 0-9 could be used in this tag so that conceivably could be a $5)
885 - Matching Information (R) Information about the results of a matching process, intended to assist catalogers in the verification of a possible match between two records.
886 - Foreign MARC Information Field (R) Used when converting foreign MARC records into the MARC format. Contains data from a foreign MARC record for which there is no corresponding MARC field. (Note that any subfield from a-z and 0-9 could be used in this tag so that conceivably could be a $5

My observation at this point - there may be approaches to specific groups of tags but the contexts for use of $5 are too variable to have a "blanket mapping". I'll say more in the discussion soon.

uwlib-cams / MARC2RDA

$5 #345