Examine source code of Search Language Switch

{
  "manifest_version": 2,
  "name": "Search Language Switch",
  "version": "0.2.0",
  "description": "Forces Google Search UI and results language to English.",
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "data/languages.js",
      "data/regions.js",
      "settings.js",
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "search-language-switch@dimik1337.dev",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {}
  },
  "browser_action": {
    "default_title": "Search Language Switch",
    "default_icon": {
      "16": "./assets/logo/logo-16x16.png",
      "32": "./assets/logo/logo-32x32.png"
    }
  },
  "icons": {
    "16": "./assets/logo/logo-16x16.png",
    "32": "./assets/logo/logo-32x32.png",
    "48": "./assets/logo/logo-48x48.png",
    "128": "./assets/logo/logo-128x128.png"
  }
}