What random parts of Mer / Nemo are closed?
And why would Mer / Nemo (again, 100% open source) have a serious overall lack of documentation? Shouldn't being open-source have fixed that by now?
Yes, absolutely! After spending millions of dollars, Jolla has built quite a nice UI on top of Mer. The problem is, those millions of dollars were not charity money. Maybe the investors will be willing to just throw away those millions of dollars and walk away, but I kind of doubt it.
Great. So, you're saying that open-source contributions can really only work at the tail end of a project, for (say) maintenance and small incremental work. Hurrah for open-source!