Examine source code of Simplify Light Clean

{
  "name": "Simplify Light Clean",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "firefox_header.png"
    },
    "colors": {
      "frame": "rgba(238, 238, 238, 1)",
      "tab_background_text": "rgba(128, 128, 128, 1)",
      "toolbar": "rgba(227, 227, 227, 1)",
      "bookmark_text": "rgba(128, 128, 128, 1)",
      "toolbar_field": "rgba(227, 227, 227, 1)",
      "toolbar_field_text": "rgba(128, 128, 128, 1)"
    }
  }
}