Examine source code of Firefox - simple.colors

{
  "theme": {
    "images": {
      "theme_frame": "persona_top_ff.jpg"
    },
    "colors": {
      "frame": "#eeeeee",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Firefox - simple.colors",
  "manifest_version": 2,
  "description": "changed... in addition: previous version has bugs in composition (i appologise users, who already get this persona)"
}