Examine source code of Bulgarian flag

{
  "theme": {
    "images": {
      "theme_frame": "bgFirefoxb.png"
    },
    "colors": {
      "frame": "#a4edb1",
      "tab_background_text": "#a1a1a1"
    }
  },
  "version": "2.0",
  "name": "Bulgarian flag",
  "manifest_version": 2
}