Examine source code of Nintendo Game Boy

{
  "name": "Nintendo Game Boy",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Nintendo Game Boy.png"
    },
    "colors": {
      "frame": "rgba(140, 173, 40, 1)",
      "tab_background_text": "rgba(33, 66, 49, 1)",
      "toolbar": "rgba(108, 148, 33, 1)",
      "bookmark_text": "rgba(33, 66, 49, 1)",
      "toolbar_field": "rgba(140, 173, 40, 1)",
      "toolbar_field_text": "rgba(33, 66, 49, 1)",
      "tab_line": "rgba(66, 107, 41, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a405521a-b0f4-4210-9331-5b1bb1bdfde2}"
    }
  }
}