title: What is emacs MRev mode?
body: <p>I could not find anything relevant after searching "MRev", so I hope someone can offer a tip.</p>
  
  <p>Here is a picture below, viewing <code>.css</code> code in <code>Text</code> mode with <code>Flyspell</code> minor mode. <code>MRev</code> does not disappear when changing files, so it appears to be a minor mode.
  <img src="https://i.stack.imgur.com/9CQTr.png" alt="enter image description here"></p>