Situation:
We plan to implement the new language code mul on Wikidata mainly to reduce the number of redundant Items (main task: T285156, next milestones: T312097). Fewer Labels in Items might have unintended consequences for some tools. Some consequences seem unavoidable (e.g. the number of Labels will be a less useful indicator for ranking Items) but we want to ensure that the change is as light as possible on users and maintainers of tools.

Community Input:
This task collects and discusses community input about

• what this change could mean for tool developers, data reusers, and editors
• ideas what we can do to make the change as easy as possible

Outcomes:

• We need to make sure that tool developers are aware of the change.
  • e.g. scripts shouldn't add the same label multiple times if an identical "mul" value is already there
• Tools that use wbgetentities: Should just work using languagefallback=1 (see T312723#8214779).
• Screen readers: We use <span lang="mul"> to indicate text in mul language code. This is common practice on the Wikimedia projects and seemed satisfactory in our tests. An alternative would have been to omit this completely. We will continuously monitor feedback on this.
• Wikidata Query Service (WDQS): Should just work after some tweaks (see T304976)

Original:
There were questions about this initiative at the Wikidata Data Quality Days 2022.