Examine source code of Ready for Spring

{
  "name": "Ready for Spring",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "TulipEnvyHH.jpg"
    },
    "colors": {
      "frame": "rgba(202, 212, 240, 1)",
      "tab_background_text": "rgba(51, 47, 47, 1)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(201, 212, 240, 0.05)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c478745b-49ea-4f3a-b1a0-8132ad128967}"
    }
  }
}