Examine source code of WordExplorer

{
  "manifest_version": 2,
  "name": "WordExplorer",
  "version": "1.0",
  "author": "HA5AST",
  "description": "Gives explanation and synonyms of selected or mouse-pointed words. Hotkey: Alt-w",
  "icons": {
    "96": "icons/wordexplorer.png"
  },
  "permissions": [
    "webRequest",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "wordexplorer.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{dcbdd16b-f6f9-4f74-a235-d3fb05ef3e15}"
    }
  }
}