With the resolution of bug 7496 this becomes less of an issue, since to link to any site you can now safely use proj:lang:PageName. JavaScript gadgets and the like simply need a small translation table { wiki: 'w', wiktionary: 'wikt', ... }. Namespace name conflicts should not be occurring with these short prefixes (if they are, please file a bug).

Of course, this does not take into account special/chapter wikis, which are a mess - but for Wikidata this is not relevant.

To some extent this is a duplicate of the original request in bug 48035, but I'm going to leave this bug open for now.

Shouldn't the abbreviated interwiki prefixes be tracked as a new column in mediawiki-core/maintenance/interwiki.sql?

In T47116#1103169, @awight wrote:

Shouldn't the abbreviated interwiki prefixes be tracked as a new column in mediawiki-core/maintenance/interwiki.sql?

What do you mean?

Well, https://gerrit.wikimedia.org/r/#/c/195464/ and T89546 caught my attention. The issue of interwiki transclusion was forced by the global user page feature, but thinking about it more, I see that the transcluded content has other problems, for example local wiki templates and links are broken as well? I'm not sure it's a good idea to start pointing all "w:" links to English Wikipedia, but as long as we're moving in this direction, perhaps we should add a new column to the interwiki sites table to help standardize these short prefixes?

start pointing all "w:" links to English Wikipedia, but as long as we're moving in this direction

Are we? O_o

Yes, I don't know where you get that idea. Currently w: points to English Wikipedia from all Wikipedias, and to the local-language version of Wikipedia from all non-Wikipedia wikis. We can't alter that, as it would break too many links.

I don't see why this would need to be included in the sites table. As far as I can see, it can be inferred from the other data there.