Examine source code of mSession Keeper

{
  "manifest_version": 2,
  "name": "mSession Keeper",
  "default_locale": "en",
  "description": "An extension to keep your sessions alive.",
  "version": "0.9resigned1",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "64": "icons/64.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": false,
    "default_icon": "icons/32.png",
    "default_popup": "popup/popup.html",
    "default_title": "mSession Keeper"
  },
  "options_ui": {
    "browser_style": false,
    "page": "options/options.html"
  },
  "permissions": [
    "notifications",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "applications": {
    "gecko": {
      "id": "multi-session-keeper@pmorzonek",
      "strict_min_version": "54.0a1"
    }
  }
}