Yeah, I too find it hard to figure out exactly who the ruby committers are, or what goes on amongst them. I believe this is simply because of that language barrier. From what I do know, the way MRI is developed is not at all atypical or unusual compared to most other large open source (primarily English-language) projects.

Here's a useful (to those curious to learn more about ruby committers) interview from 2013 with 15 ruby committers, note the questions and answers have been translated between English and Japanese. http://www.sitepoint.com/meet-fifteen-ruby-core-committers/

My impression is that a lot of discussion on MRI happens in Japanese on Japanese listservs. Of course, it doesn't take a language barrier to make things seem not so transparent -- for comparison a few years ago, Rails core team started taking the majority of their discussion to private core-team-only listservs. (I gather because they were finding dealing with the peanut gallery made it too hard to get things done/decided). At least there's still lots of open (and English-language) communication on the github issues or open listserv, but there are often times when I'm not really sure who or how or on what basis architectural decisions are made for Rails too, a lot is done in private, is my impression.

But I suspect to curious Japanese-speakers, MRI development may even be _more_ transparent than Rails is to English-speakers! I think (but not entirely sure) all of the listservs MRI devs use to collaborate are actually open -- you just have to read/write Japanese to understand what's there or engage effectively. :)