Examine source code of Webpage Eraser

{
  "manifest_version": 2,
  "name": "Webpage Eraser",
  "version": "2.0.1",
  "description": "Erase selected visible elements from the current webpage.",
  "icons": {
    "16": "icon/icon_16.png",
    "48": "icon/icon_48.png",
    "128": "icon/icon_128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icon/icon_48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "crx-webpage-eraser@warren-bank.github.io"
    }
  }
}