Examine source code of Retainer

{
  "licence": "This Source Code Form is subject to the terms of the Mozilla Public License, v2.0. If a copy of the MPL was not distributed with this file, you can obtain one at https://mozilla.org/MPL/2.0/",
  "copyright": "© 2017 Jonathan Kingston, © 2021 Roy Orbison",
  "manifest_version": 2,
  "name": "Retainer",
  "author": "Roy Orbison",
  "version": "0.2.1",
  "description": "Provides a keyboard shortcut (Shift + Alt + C by default) to create a new tab that retains current/last-used container.",
  "icons": {
    "16": "icon.svg",
    "32": "icon.svg",
    "48": "icon.svg",
    "96": "icon.svg",
    "128": "icon.svg",
    "512": "icon.svg"
  },
  "homepage_url": "https://github.com/Roy-Orbison/Retainer",
  "browser_specific_settings": {
    "gecko": {
      "id": "retainer@roy-orbison.test",
      "strict_min_version": "58.0a1"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "notifications",
    "tabs",
    "storage",
    "cookies"
  ],
  "commands": {
    "retainer-tab": {
      "suggested_key": {
        "default": "Shift+Alt+C"
      },
      "description": "New retained tab"
    }
  },
  "options_ui": {
    "page": "options.html"
  }
}