Examine source code of Multi-Tab Close

{
  "description": "Close multiple tabs",
  "manifest_version": 2,
  "name": "Multi-Tab Close",
  "version": "0.5.4resigned1",
  "developer": {
    "name": "Jagan",
    "url": "https://github.com/j70/multitabx"
  },
  "icons": {
    "16": "icons/icon.svg",
    "32": "icons/icon.svg",
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "storage",
    "contextMenus",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Close Tabs",
    "default_icon": "icons/icon.svg"
  },
  "short_name": "MultiTabX",
  "applications": {
    "gecko": {
      "id": "multitabx@j70.user.github.com",
      "strict_min_version": "48.0"
    }
  }
}