There are two different issues here:

If you want mw: to be used from Wikimedia projects, it should be added to Wikimedia interwiki table (seems to be already there, even for commons).

If you want foreign wikis to link to mediawiki.org, it should be added to the provided default interwikis (as [[mediawiki: ]] perhaps?)

(In reply to comment #1)

There are two different issues here:

If you want mw: to be used from Wikimedia projects, it should be added to
Wikimedia interwiki table (seems to be already there, even for commons).

This is what he seems to be asking for.

If you want foreign wikis to link to mediawiki.org, it should be added to the
provided default interwikis (as [[mediawiki: ]] perhaps?)

We do provide it by default as 'mediawikiwiki.' Using 'mediawiki' would conflict with the Mediawiki: namespace.

gangleri wrote:

(In reply to comment #0)

Today [[meta:mw:Extension:SpecialInterwiki]] and
[[m:mw:Extension:SpecialInterwiki]] are useful links.

This will not work here.

Trying [[mw:Extension:SpecialInterwiki]] ...

gangleri wrote:

(In reply to comment #3)

...
Trying [[mw:Extension:SpecialInterwiki]] ...

This will not work here.

(In reply to comment #2)

(In reply to comment #1)

There are two different issues here:

If you want mw: to be used from Wikimedia projects, it should be added to
Wikimedia interwiki table (seems to be already there, even for commons).

This is what he seems to be asking for.

Exactly! It is a very useful first step.

Adding a interwiki prefix to the default interwiki table is a very good idea but was not requested in this enhancement request.

gangleri wrote:

PS: It seems that there will be no conflict with pages starting wit mw [[commons:special:PrefixIndex/mw]].

It is not redirecting, but links on meta: http://meta.wikimedia.org/w/index.php?title=Meta:Sandbox&oldid=1795141
Bugzilla uses a different interwiking...

gangleri wrote:

two issues:
a) http://meta.wikimedia.org/w/index.php?title=Template:MediaWiki_links&action=edit shows that mw: is a valid interwiki link at meta:

b) while some interwiki prefixes can be used in combination ( thgey can be cascaded) mw: can not be used as a second interwiki prefix. I appologize about this detail. It seems to be another enhancement request.

In order to understand the background of this request please take a look at some interwiki linking at
http://wikieducator.org/Talk:Language_Installations#interwiki_linking_at_WikiEducator

I tried to use an interwiki prefix chain also at http://www.librarything.com/ but it seems that there is no chance.

Marking this worksforme. mw is a (non-local) interwiki on commons.

Making mw: a local interwiki (so it will work in interwiki "chains") is bug 22407

You can place the following on any WMF wiki page (be in Wikipedia, Meta or Commons)

[[mw:Test]]

and it will work, today.

However it wont work via the URL address or in chains like [[meta:w:de:mw:Test]] (which is quite useless since there is only 1 "mw", no need for chaining).

There's a bug already under id bug 22407 which requests to make "mw" a local iw prefix, so that's it's chainable and usable in the url (like [[meta:w:de:mw:Test]]).