Examine source code of What3words translator

{
  "description": "Translate from coordinates to 3 words and vice versa",
  "manifest_version": 2,
  "name": "What3words translator",
  "version": "1.1",
  "icons": {
    "48": "icons/icon.png"
  },
  "permissions": [
    "webRequest",
    "tabs",
    "<all_urls>"
  ],
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_title": "Translator",
    "default_popup": "popup/w3w.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "replacer.js"
      ]
    }
  ]
}