Examine source code of Remove-Everything

{
  "description": " Firefox addon to remove anything from history, passwords, downloads to serviceWorkers",
  "manifest_version": 2,
  "name": "Remove-Everything",
  "version": "1.1resigned1",
  "homepage_url": "https://github.com/nabendu82/RemoveEverything",
  "icons": {
    "32": "icons/logo_32.png",
    "48": "icons/logo_48.png",
    "64": "icons/logo_64.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "Remove it!"
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "permissions": [
    "browsingData",
    "notifications",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e7c2835a-024c-4488-b37f-8cce374ea9e9}"
    }
  }
}