Examine source code of weblioSearch

{
  "manifest_version": 2,
  "name": "weblio_search",
  "version": "2.6.2",
  "description": "右クリックにweblio検索を追加します",
  "permissions": [
    "notifications",
    "contextMenus",
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "main.js"
      ]
    }
  ]
}