Examine source code of Pencil Flowering

{
  "name": "Pencil",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "pencil.png"
    },
    "colors": {
      "frame": "rgba(143, 143, 143, 0.34)",
      "tab_background_text": "rgba(240, 240, 240, 1)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(240, 240, 240, 1)",
      "toolbar_field": "rgba(115, 115, 115, 0.62)",
      "toolbar_field_text": "rgba(240, 240, 240, 1)",
      "tab_line": "rgba(97, 97, 97, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a3779426-2355-4ee1-a9bd-5e6118f48591}"
    }
  }
}