Not to start a debate about this but the entire tractor is made off of the Kioti frame and chassis and is fairly well identical besides paint. You will even here of bobcat owners getting scratches on their machines and it being Kioti orange underneath. To make the same example with John Deere, John Deere owns hitachi construction who makes excavators. They are identical except color. Not that it matters I would just prefer the original. No real reason beyond that. One of the rare situations that the bobcat actually has a bigger brand name than the who they are having the tractor made by, Kioti. In the case you mention with a John Deere actually being a Yanmar because it has a Yanmar engine is like saying if you pull a duramax diesel from a Chevy truck and put it in a ford the ford becomes a Chevy because that's the engine it has. Kioti makes bobcats frame, the hood, the cab, the ROPS, the loader. They make the whole tractor. Yanmar makes an engine and John deere designs and builds everything else. The loader, frame etc. Not that bobcat/Kioti is a bad thing. If I were to get either of those I would get a Kioti. If I were to get any of the three I would get a Deere. But now were completely off topic.
And btw. Deere makes its own engines for most of its tractors on the 4x20 series and up.