Examine source code of Content Remover

{
  "manifest_version": 2,
  "name": "DOM-eraser",
  "version": "0.2",
  "description": "Remove unwanted DOM elements by clicking.",
  "icons": {
    "48": "icons/dom-eraser-icon.svg",
    "96": "icons/dom-eraser-icon.svg"
  },
  "browser_action": {
    "default_icon": "icons/dom-eraser-icon.svg",
    "default_title": "DOM-eraser"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_scripts/app.js"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}