Examine source code of Cookie Lympha

{
  "name": "Lympha",
  "description": "Remove cookies of the specific site.",
  "manifest_version": 2,
  "version": "1.1resigned1",
  "homepage_url": "https://github.com/MARNUTUX/lympha-cookies",
  "applications": {
    "gecko": {
      "id": "@lympha",
      "strict_min_version": "48.0"
    }
  },
  "icons": {
    "48": "data/icon.png"
  },
  "permissions": [
    "tabs",
    "<all_urls>",
    "cookies",
    "notifications",
    "contextMenus",
    "storage"
  ],
  "browser_action": {
    "default_icon": "data/icon.png",
    "default_title": "Clean it!"
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "default_locale": "en",
  "commands": {
    "toggle-feature": {
      "suggested_key": {
        "default": "Ctrl+Shift+L"
      },
      "description": "Remove cookies"
    }
  }
}