Not everything that Ubuntu is doing is in the open. They're using a lot of other people's code, and aren't contributing back. Not yet and probably not until after they've made their money from those changes... Sorta something like that. I'm trying to convey quickly what seems to be a very troubling situation. And I'm definitely not exactly the best person to answer since I don't know all of which code and/or libraries are being used: think it started around libhybris.
No, it started much earlier, during the first mer days. OG Mer was to be (toting the familliar hildon-desktop) the ubuntu mobile distribution back in the days of karmic. I'll leave the details of what happened as an exercise to the reader as I don't know the exact facts and I don't want to misinform.