We stan a mito story! My old lab discovered some of what we called "kiss and run" dynamics: https://en.wikipedia.org/wiki/Kiss-and-run_fusion
Which had to do with watching live mitos exchange their insides. Specifically, to watch this process, you load your mitos with photoactivatable fluorophores, then use a laser to tag some which changes say your green emitting protein to red. Then you follow the color changed particles being exchanged between mitos. Same mechanism probably used here to watch cells swap mitos. Oh, and this has to be done with live cells.
Very cool stuff, mitos are so important to metabolism and more I hope we see mitohacking, as mentioned by perrygeo. A much safer performance enhancer when it's your own mitos.