Examine source code of Birch Forest

{
  "name": "Birch Forest",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "BirchForestHCustom.jpg"
    },
    "colors": {
      "frame": "rgba(153, 163, 184, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(151, 161, 184, 0)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(151, 161, 184, 0.07)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(240, 89, 8, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{093b70fd-2c10-4d2e-9a57-2d1183d1fbad}"
    }
  }
}