"Lots of potential donors to the WMF could be coaxed into pulling the trigger if they were given assurance that their contributions would serve to keep their own MediaWiki projects running smoothly."
That's not what WMF and it's 501(c)3 non-profit donated funds are there for. WMF donations are (in some countries) tax-deductible as a contribution to "adult education" as a charitable endeavour, but that's only possible because the money is supposedly going to assemble and give away a free encyclopaedia.
If the extension is actually needed for deployment on WMF sites, fine.
If not, what does any of this have to do with building an encyclopaedia?
I don't think that's really a fair interpretation of IRS code or WMF's mission statement..
- "The mission of the Wikimedia Foundation is to empower and engage people around the world to collect and develop educational content under a free license or in the public domain, and to disseminate it effectively and globally.
- In collaboration with a network of chapters, the Foundation provides the essential infrastructure and an organizational framework for the support and development of multilingual wiki projects and other endeavors which serve this mission. The Foundation will make and keep useful information from its projects available on the Internet free of charge, in perpetuity."
A lot of that language talks about broad applications, supporting an infrastructure, etc. To me, all of that covers the development of tools, like extensions, used by other free-content wiki participating in the broader MediaWiki community of projects that "empower and engage people around the world to collect and develop educational content under a free license or in the public domain."
I can wrap my head around this not applying to wikis that are private, or for-profit in nature. However, supporting tools available to any wiki and used by a several different wikis, then paying for it with donations by corporate interests isn't much different than WMF taking corporate donations from companies that have an interest in WMF's software, existence, etc. - such as Microsoft, Facebook and Google. This is pretty typical in the world of nonprofits. A community film festival sponsored by Sony, nonprofit museum's launch party sponsored by Absolut, college video game competition sponsored by Microsoft - there are a number of good examples of what I think Badon is referring to already being applied in similar nonprofits.
See my comments elsewhere for more thoughts on related topics..
By "the development of tools, like extensions, used by other free-content wiki participating in the broader MediaWiki community of projects that 'empower and engage people around the world to collect and develop educational content under a free license or in the public domain'" would that not be Wikipedia or other *very similar in objectives* projects (such as Enciclopédia Libre in Seville)?
I can't see most of the fancruft on Wikia being "educational content" or that site's mission to take other people's content and bury it under ever-increasing quantities of advertising to be a charitable endeavour. Wikia's investors might love to see an extension invented that makes the site look exactly like Facebook... but what would that have to do with collecting and developing educational content of any kind?
Likewise, would Uncyclopedia and extension:RandomSelection qualify? They're amusing, but I have the sneaking suspicion that their only enduring educational accomplishment is to lower the collective IQ of Brazil at least two or three points since the first Desciclopédia article was written in 2005, with similar but lesser results in other countries where various languages of Uncyclopedia operate.
If this were something like Extension:Cite or Extension:Math, which is used in the encyclopaedia, sure - treat them as if they were core code. The same would not apply, though, to the seemingly-endless efforts to keep inventing and reinventing more extensions to turn a wiki into an endless collection of links to YouTube (for which we have too many extensions already).
The more closely aligned the extension is to the interests of the ones helping to maintain the extension, the more attention it will be given.
For WMF help, extension maintenance for Wikia, etc, may be limited to just advisory assistance with updates to keep them compatible with current versions of MediaWiki. For independent volunteers, they can do much more than that while receiving the same kind of advisory assistance from WMF.
Cite, Math, and anything else likely to have broad public benefit can have unlimited attention from WMF, as needed.
Hopefully it is clear to you that there's nothing about this that instantly leads to certain doom. Resources can be allocated according to the greatest benefit, but no one should be left out completely.