title: What is a stash?
body: <p>I have googled and searched in various places for a while, but have not found a good answer. What is a stash, and what is it used for?</p>
  
  <p>(Source of confusion: using beautiful Fuel with Fossil, clicked the "Stash changes" button, see files in there with question marks, and don't know what to do with them ...)</p>