Examine source code of Spuffy 4

{
  "theme": {
    "images": {
      "theme_frame": "spuffyheader4-cream.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Spuffy 4",
  "manifest_version": 2,
  "description": "Spike and Buffy belong to Mutant Enemy, of course. (If the image is cut off: This looks better if you right-click to customize your toolbar area and add a new toolbar or two, but you have to put at least one thing in the toolbar for it to work.)"
}