Examine source code of Remove Tel Links

{
  "manifest_version": 2,
  "name": "Remove Tel Links",
  "version": "1.1resigned1",
  "description": "Remove links for phone numbers.",
  "icons": {
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "remove_tel_links.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f3affb87-678c-479d-bd69-7095e0ffa731}"
    }
  }
}