It adds a menu that puts h1, h2 and so on, right at your fingertips. It includes a couple of nice little undo/redo buttons. It looks like this:

It does not much else, yet. My mad skilz are about as pathetic as the phrase “mad skilz” sounds. But I figure my minor annoyance with Tumblr’s limited editing functionality can be your less-minor annoyance. To install this, add Greasemonkey or Tampermonkey to your browser, or as some might call it, your rig.

Happy holidays. — Ernie @ SFB