Examine source code of Inject Custom JS and CSS

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0.0",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "author": "Iván Ros",
  "homepage_url": "https://github.com/IvanRosNavarro/inject-code-for-firefox",
  "icons": {
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "<all_urls>",
    "webNavigation"
  ],
  "browser_action": {
    "default_icon": "icons/icon.svg",
    "default_title": "Inject Custom JS and CSS",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "inject-custom-js-and-css@ivanros.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}