Examine source code of bpg

{
  "name": "bpg",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Untitled.png"
    },
    "colors": {
      "frame": "rgba(218, 140, 219, 1)",
      "tab_background_text": "rgba(250, 250, 250, 1)",
      "toolbar": "rgba(168, 161, 161, 1)",
      "bookmark_text": "rgba(150, 92, 92, 1)",
      "toolbar_field": "rgba(194, 144, 144, 1)",
      "toolbar_field_text": "rgba(250, 250, 250, 1)",
      "tab_line": "rgba(148, 127, 127, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d5808264-1642-494a-90d1-9d5b8adadcd2}"
    }
  }
}