Examine source code of Automatic Tab Discarder

{
  "manifest_version": 2,
  "name": "Tab Discarder",
  "version": "1.0",
  "description": "Automatically discard inactive tabs to free up memory",
  "author": "Tab Discarder",
  "permissions": [
    "tabs",
    "storage",
    "alarms"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Tab Discarder",
    "default_icon": {
      "48": "icons/icon.png"
    }
  },
  "icons": {
    "48": "icons/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-discarder@extension",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}