Examine source code of VisaOnline

{
  "name": "Tadashi Hamada",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Tadashi Hamada.png"
    },
    "colors": {
      "frame": "rgba(94, 140, 247, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(69, 77, 237, 0.28)",
      "toolbar_field": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{be78be9d-ccf5-4d4d-9905-2f5384754adf}"
    }
  }
}