Examine source code of remove_wiki_add

{
  "manifest_version": 2,
  "name": "remove_wiki_add",
  "description": "Turn off wikipedia ads.",
  "version": "1.0.1",
  "icons": {
    "48": "static/icons/icon.jpg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://ja.wikipedia.org/*"
      ],
      "js": [
        "src/index.js"
      ]
    }
  ]
}