Examine source code of Blessing Feather

{
  "name": "Blessing Feather",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "3000x200Firefox2023年4月分(完成形・350dpi).png"
    },
    "colors": {
      "frame": "rgba(143, 116, 249, 1)",
      "tab_background_text": "rgba(252, 197, 225, 1)",
      "toolbar": "rgba(255, 255, 255, 0.2)",
      "bookmark_text": "rgba(252, 197, 225, 1)",
      "toolbar_field": "rgba(255, 255, 255, 0.2)",
      "toolbar_field_text": "rgba(252, 197, 225, 1)",
      "tab_line": "rgba(156, 255, 220, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4e51e010-4034-4cd9-9b9a-70eba5d540af}"
    }
  }
}