Examine source code of RedactKit

{
  "manifest_version": 2,
  "name": "RedactKit",
  "version": "3.0",
  "description": "Hide user-defined sensitive words from any website.",
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Redactkit",
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icons/redacted.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "icons": {
    "128": "icons/redacted.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{699298ad-4444-4448-9408-d36f23ea2a69}"
    }
  }
}