I'd be opposed to this. The project namespace config works just fine and there's no reason to pretend it doesn't just to work around a shortcoming in the interwiki system.

What is the specific shortcoming in the interwiki system you're talking about, and how would we fix it? Also, what is the advantage of encouraging wikis to use a project namespace name that's the same as the wiki name? I would think it would be more convenient to standardize it to Project: because then if you port content from one wiki to another that has links to Project: you don't need to do a find-and-replace to change, e.g. "FooWiki:Sandbox" to "BarWiki:Sandbox". It will just be "Project:Sandbox" on both wikis, and the imported page would fit right in.

We standardize the other namespace names (MediaWiki:, Template:, Help:, etc.) from one wiki to the next, so why not standardize Project: too?

The whole thing is a shortcoming. I agree with Tim on list that we should kill them :)

We're still awaiting an explanation of how, without interwikis, we'd handle mythical interwiki transcluding. Most of the other mythical use cases, such as interwiki page existence checking, merely require an API URL. [[mw:Requests for comment/New sites system]]

Even if we scrapped interwikis, though, it would still be slightly more convenient to have Project: be standardized for situations in which people want to import project namespace pages from other wikis. As it is, if I import FooWiki:Policy, it ends up in the mainspace of my local wiki, and I have to move it to Project:Policy. Also, any wikilinks to FooWiki: pages have to be edited to point to Project: (or BarWiki:) pages (or to be external links). The only advantage I can see to the current system would be if we WANTED those links to break when the pages are ported.

I guess if the interwiki prefixes were scrapped, one could make Wikipedia: be a namespace alias for Project:, and then the imported wikilinks wouldn't break.

Change 109056 had a related patch set uploaded by leucosticte:
Make "Project" the default meta namespace

https://gerrit.wikimedia.org/r/109056

(Responding to Brian Wolff's Gerrit code review comment "I'm not sure how I feel about this. Calling the project namespace after the wiki name is a pretty long established tradition")

Is the main concern that people will type in FooWiki:BarPage and be surprised to find that namespace doesn't exist? What are the main problems that might be caused?

My concern is more that this is changing the way something has been done for a very long time, which has somewhat become ingrained into the way mediawiki works, and I'm not sure the problem it is fixing justifies changing the behaviour (Also change is scary!).

The change that Tim and Chad are talking about, of scrapping interwiki prefixes entirely, is even more radical (and therefore scarier). But if any change will be implemented, it seems to me that the least disruptive way of doing it is to make a change in the installer, because then one is not making a change to existing wikis. Of changes made to the installer, the least disruptive of those is to change the default option while still leaving the former default available.

An alternative way to introduce change would be for someone to go to [[Project:Village pump (proposals)]] and say, "Hey guys, why don't we all start using Project: as the project namespace prefix instead of Wikipedia:? Once all uses of Wikipedia: have been replaced, it'll be easier to make a case for retiring Wikipedia: entirely as a namespace prefix. Think how that would benefit third-party wikis that want to import our content!"

That proposal having been enthusiastically accepted and implemented, and similar proposals having been similarly enthusiastically accepted and implemented at other major wikis, it would be easier to make a case for changing the installer default.

(In reply to comment #8)

An alternative way to introduce change would be for someone to go to
[[Project:Village pump (proposals)]] and say, "Hey guys, why don't we all
start
using Project: as the project namespace prefix instead of Wikipedia:? Once
all
uses of Wikipedia: have been replaced, it'll be easier to make a case for
retiring Wikipedia: entirely as a namespace prefix. Think how that would
benefit third-party wikis that want to import our content!"

That proposal having been enthusiastically accepted and implemented, and
similar proposals having been similarly enthusiastically accepted and
implemented at other major wikis, it would be easier to make a case for
changing the installer default.

Regardless of whatever happens with the installer, I'm pretty sure we are not going to change the project namespace name on existing wikimedia wikis.

Added link to [[mw:Media:ProjectDefaultNamespace.png]], illustrating what the new default looks like in the installer.

Oh yeah, another advantage of calling it Project: is that if you ever change the name of the wiki, you don't have to worry about that namespace changing to a different name (which would require changing all the links to its pages). Mises Wiki is probably about to become Bastiat Wiki, as it changes hands from the Mises Institute to the Bastiat Institute. Similarly, Libertarian Wiki became Libertapedia. So many wikis are forked, or incorporated into larger wikis, or eventually change ownership, in the world of third party wikis, which can necessitate name changes.

Plus Project: is usually shorter than the name of the wiki, so that saves keystrokes.

Its trivial to add aliases in that case, or just keep the old name.