Better late than never I guess, hopefully we'll get enough modules here to reduce the ones in our local wikis to the bare minimum. 

We still need a good policy for protecting modules considering that unlike wikipedia there's currently no way of getting the usage of the module.

I added the module:devmodule to w:Template:dev, and it seems to work perfectly as a global module/template. So theoretically all wikias can access any module hosted here through it without creating any templates on their own wikias. 

Until the cache clears up it will still showing the old data though.

Just to let you know, you are not allowed under any circumstances to transclude article templates from Community Central.

{{:user:dessamator/test}}?

You can interwiki transclude hub templates and user page templates, that is it. You cannot transclude the dev template on Community Central on any other wiki. That would constitute a global transclusion and that puts too much strain on the server.

{{w:dev}}

Doing this is strictly not allowed across the board.

{{w:dev}}

I wasn't even aware that would work let alone that it wasn't allowed, so I didn't even try. Although staff once told me that that kind of stuff is called scary transclusion for a "reason". Wikimedia still hasn't found a way to make it "less" scary with all their endless bureaucracy.

Anyway, what that template currently does is simply invoke a module that in turn invokes a global module (from dev.wiki). In essence it is doing exactly what the developers designed global module transclusion for, as far as I can tell.

{{w:dev}}

Edit:

What you just said contradicts the Help:Shared_templates though:

Shared templates Help:Templates that can be used across Wikia.

If you're right, you should probably contact staff to amend it then.

I fixed a link to w:Template:Dev above, to avoid any confusion when you get redirected to Templates Wiki.

To add a comment to the discussion about creating global templates, user page templates are often transcluded from community central (and have been for years). As far as I know, it's never used for article templates, likely because articles are edited more often and thus add more stress to the servers than a normal user page. It uses a completely different system to global modules which relies on wikia specific code which is similar to how the central help page repository works.

There's some notes about the template transclusion on mw:Manual:$wgEnableScaryTranscluding if anyone's interested too.

My question is whether global modules don't have the same drawbacks as global templates and wikia is maybe just hoping that they will never be widely used, so it will never cause serious performance issues.

Also, that page indicates that it is outdated, so one would wonder which parts of it are right and which aren't.

Now that I think of it, theoretically, if we move a lot of templates from somewhere and store them here, we could simply use frame:preprocess to have access to all templates here in the same way that they are accessible from community central. Although there'll be a performance hit, I guess.

No, global modules do not have the same drawbacks. Wikia has a database that's shared between all wikis, as can be seen from the global user database. It allows them to access the help pages stored on community central anywhere on wikia, and is probably used for the resourceloader modifications that allow interwiki js/css loading. This is what's used to access modules on dev, which is very much different to the template transclusion.

That notice looks to have been added by a bot, with no reference as to why it's been outdated. It might have been an artefact of a mediawiki upgrade (so someone thought it might need checking) or it might be a reflection of the changes in how globals are handled in mediawiki or it might be something else entirely. Since wikia is now 6-7 version behind the developed version of mediawiki I would guess it's still pretty accurate for our purposes.