Examine source code of Discard Tab

{
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0.4resigned1",
  "homepage_url": "https://github.com/freddyb/webext-discard-tab",
  "default_locale": "en",
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon.png"
  },
  "applications": {
    "gecko": {
      "id": "{09420bd6-3c35-444d-b85c-74d51fe3df4f}",
      "strict_min_version": "58.0a1"
    }
  },
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "menus"
  ],
  "optional_permissions": [
    "<all_urls>"
  ],
  "options_ui": {
    "browser_style": true,
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}