@Kghbln Yes, it is included in wmf, but this extension is not supported by any developer or group.
Topic on Extension talk:Babel/Flow
Well, this is also true to some other extensions run on WMF wikis but in this case the language team takes care of it since it is part of MLEB.
The Language team says that they don't support extension. You can see it in Maintenance responsibilities. And this is strange.
Yeah, I also think this appears to be bulsh. I would think that one should either remove it from the bundle or do at least hot fixes. However the extension would create a really big fuss if it were not working on the foundation wikis so I still think this justifies the status as being maintained. I am sure somebody will do the hot fix.
I've already tried to find someone: https://discuss-space.wmflabs.org/t/who-oversees-the-babel-extension/653/
I don't know where this thread got started, but a look at https://gerrit.wikimedia.org/r/q/project:mediawiki%252Fextensions%252FBabel tells that the extensions is maintained.
That is not the same thing as someone officially listed as being maintainer of it. It seems that you are looking for active maintenance with PM and UX support, and that is hard to find even for better maintained extensions.