Examine source code of Element Picker - NAC

{
  "manifest_version": 2,
  "name": "Element Picker - NAC",
  "version": "3.1",
  "description": "Hide unwanted elements and text on websites.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "<all_urls>",
    "tabs",
    "contextMenus"
  ],
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Element Picker - NAC",
    "default_popup": "management.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8d669291-dfa3-402b-a624-91b016a598bf}"
    }
  }
}