Not really, most editors support the ability to duplicate a line using CMD+D, including AppCode by JetBrains. In my case, using Colemak, S is mapped to D, and s

Not really, most editors support the ability to duplicate a line using CMD+D, including AppCode by JetBrains. In my case, using Colemak, S is mapped to D, and so if I'm in the wrong keyboard layout, I'll go to save and end up duplicating a line, then saving by hitting the right key. If I'm not careful, I'll have saved a duplicate line without noticing. Similarly, given how the rest of the changes seemed to be attempts to rename and clean up the API, I expect that it was a junior intern cleaning up code as a whole. It would be more interesting to see the history of the commits, but that's not public (that I know of). It does highlight how we get that data with Google's Android, even though the development and release process is basically the same.