"For something to be enabled in production on the Wikimedia servers it is a requirement that all parts are freely licensed and can be used in multiple languages (MediaWiki exists in 371 languages and Wikipedia on 291)"
And also rather important, it needs to pass a security review by the security team. This usually holds up MANY extensions, for good reasons (it's just not safe) and for bad reasons (security team doesn't have time). Please keep that on your radar.