Examine source code of ProxyContain

{
  "manifest_version" : 2 ,
  "name" : "ProxyContain",
  "version" : "1.7",
  "description" : "Proxy Container",
  "homepage_url" : "https://github.com/dfuribez/proxycontain",
  "icons" : {
    "128" : "res/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "proxy@contain",
      "strict_min_version": "91.1.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions" : [
    "activeTab" ,
    "contextualIdentities" ,
    "cookies" ,
    "webRequest" ,
    "webRequestBlocking" ,
    "<all_urls>" ,
    "proxy" ,
    "storage" ,
    "scripting" ,
    "tabs" 
  ],
  "browser_action" : {
    "default_icon" : "res/icon.png",
    "default_title" : "Proxy Contain",
    "default_popup" : "popup/popup.html"
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "options_ui" : {
    "page": "settings/settings.html" 
  },
  "content_scripts" : [
    {
      "matches" : [
        "<all_urls>" 
      ],
      "js" : [
        "content.js" 
      ],
      "run_at" : "document_start" 
    }
  ]
}