Examine source code of Blue something

{
  "theme": {
    "images": {
      "theme_frame": "firefoxheader.png"
    },
    "colors": {
      "frame": "#0adafa",
      "tab_background_text": "#0adafa"
    }
  },
  "version": "2.0",
  "name": "Blue something",
  "manifest_version": 2,
  "description": "Something blue :D"
}