Feature summary (what you would like to be able to do and where):
See https://www.wikidata.org/wiki/Wikidata:Requests_for_comment/Duplicate_References_Data_Model_and_UI
- Condense internal JSON storage for duplicate references
- Modify the Wikidata UI for editing duplicated references
Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
As an example see Q21481859 in Wikidata, which has almost 3000 authors who (should) all have the same reference; the duplicated reference data accounts for over 1 MB of the 4.4 MB size of the item. Wikidata items have a maximum JSON file size of about 4.4 MB so the reference duplication has made this and similar items almost un-editable.
See also comments on the Wikidata RFC - the DuplicateReferences gadget and the "UseAsRef" script are widely used.
Benefits (why should this be implemented?):
First, this would help significantly reduce the size of many large Wikidata items, making them more usable and editable.
Second, this would allow a number of UI changes to improve the experience of adding and maintaining references in Wikidata.
I will also link some related tasks that may be resolved through this work.