Examine source code of Oropen — learn languages with subtitles

{
  "manifest_version" : 3 ,
  "name" : "__MSG_extName__" ,
  "description" : "__MSG_extDescription__" ,
  "version" : "0.4.2",
  "icons" : {
    "16" : "icons/16.png",
    "32" : "icons/32.png",
    "48" : "icons/48.png",
    "128" : "icons/128.png"
  },
  "default_locale" : "en" ,
  "permissions" : [
    "storage" ,
    "identity" ,
    "scripting" 
  ],
  "host_permissions" : [
    "https://api.oropen.com/*" ,
    "https://www.youtube.com/*" ,
    "https://www.netflix.com/*" ,
    "https://oropen.com/*" 
  ],
  "optional_host_permissions" : [
    "*://*/*" 
  ],
  "action" : {
    "default_title" : "Oropen",
    "default_popup" : "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a5310136-ab18-4f9e-a7a8-f799405bcc6c}",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "authenticationInfo",
          "websiteContent"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "content_scripts" : [
    {
      "matches" : [
        "https://www.netflix.com/*" 
      ],
      "run_at" : "document_start" ,
      "js" : [
        "content-scripts/netflix-main.js" 
      ],
      "world" : "MAIN" 
    },
    {
      "matches" : [
        "https://www.netflix.com/*" 
      ],
      "run_at" : "document_idle" ,
      "js" : [
        "content-scripts/netflix.js" 
      ]
    },
    {
      "matches" : [
        "https://oropen.com/*" 
      ],
      "run_at" : "document_idle" ,
      "js" : [
        "content-scripts/site-bridge.js" 
      ]
    },
    {
      "matches" : [
        "https://www.youtube.com/*" 
      ],
      "run_at" : "document_start" ,
      "js" : [
        "content-scripts/youtube-main.js" 
      ],
      "world" : "MAIN" 
    },
    {
      "matches" : [
        "https://www.youtube.com/*" 
      ],
      "run_at" : "document_idle" ,
      "js" : [
        "content-scripts/youtube.js" 
      ]
    }
  ]
}