Examine source code of Auto Tab Discard PM

{
  "manifest_version": 2,
  "name": "Auto Tab Discard",
  "version": "1.3",
  "description": "Automatically discards inactive tabs to save memory. Smart rules, whitelist, context menu, and keyboard shortcut.",
  "permissions": [
    "tabs",
    "storage",
    "alarms",
    "idle",
    "contextMenus",
    "notifications",
    "webNavigation"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_icon": "icons/logo_128.png",
    "default_title": "Auto Tab Discard",
    "default_popup": "options.html"
  },
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "commands": {
    "discard_current_tab": {
      "suggested_key": {
        "default": "Alt+Shift+U"
      },
      "description": "Discard the current tab"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ff558c82-0dba-4873-bb0c-e9d800d14fa7}"
    }
  }
}